Apoun placing a few Infernal Bricks the game Crashes with an NPE
Can't enter the same world or anything.

• Head --
  Stacktrace:
  at net.minecraft.client.renderer.ItemRenderer.func_78446_a(ItemRenderer.java:605)
  at net.minecraft.client.renderer.ItemRenderer.func_78447_b(ItemRenderer.java:556)
  at net.minecraft.client.renderer.EntityRenderer.func_78476_b(EntityRenderer.java:705)
  at net.minecraft.client.renderer.EntityRenderer.func_78471_a(EntityRenderer.java:1271)

-- Affected level --
Details:
Level name: MpServer
All players: 1 total; [EntityClientPlayerMP['ExodusDeath'/215, l='MpServer', x=-275.72, y=61.62, z=-223.47]]
Chunk stats: MultiplayerChunkCache: 441
Level seed: 0
Level generator: ID 00 - default, ver 1. Features enabled: false
Level generator options:
Level spawn location: World: (-277,64,-148), Chunk: (at 11,4,12 in -18,-10; contains blocks -288,0,-160 to -273,255,-145), Region: (-1,-1; contains chunks -32,-32 to -1,-1, blocks -512,0,-512 to -1,255,-1)
Level time: 5931360 game time, 6089175 day time
Level dimension: 0
Level storage version: 0x00000 - Unknown?
Level weather: Rain time: 0 (now: false), thunder time: 0 (now: false)
Level game mode: Game mode: survival (ID 0). Hardcore: false. Cheats: false
Forced entities: 64 total; [EntityItem['item.tile.stonebrick'/136, l='MpServer', x=-269.19, y=52.13, z=-225.88], EntityChicken['Chicken'/139, l='MpServer', x=-248.47, y=69.56, z=-293.84], EntityBat['Bat'/141, l='MpServer', x=-244.69, y=40.00, z=-224.25], EntityPig['Pig'/140, l='MpServer', x=-251.75, y=70.00, z=-276.59], EntityItem['item.tile.stonebrick'/129, l='MpServer', x=-274.94, y=65.13, z=-227.44], EntityItem['item.tile.stonebrick'/128, l='MpServer', x=-273.88, y=58.13, z=-225.16], EntityBat['Bat'/131, l='MpServer', x=-272.47, y=43.09, z=-206.53], EntityItem['item.tile.stonebrick'/130, l='MpServer', x=-272.78, y=64.13, z=-224.13], EntityItem['item.tile.stonebrick'/133, l='MpServer', x=-271.72, y=58.13, z=-225.75], EntityItem['item.tile.dirt'/135, l='MpServer', x=-271.13, y=58.13, z=-225.88], EntityItem['item.tile.dirt'/134, l='MpServer', x=-270.03, y=52.13, z=-225.59], EntitySheep['Sheep'/152, l='MpServer', x=-218.50, y=70.00, z=-214.91], EntitySheep['Sheep'/153, l='MpServer', x=-221.84, y=71.50, z=-215.59], EntitySheep['Sheep'/154, l='MpServer', x=-213.47, y=68.00, z=-213.19], EntitySheep['Sheep'/159, l='MpServer', x=-201.94, y=73.00, z=-291.06], EntityBat['Bat'/385, l='MpServer', x=-303.50, y=21.00, z=-173.50], EntitySheep['Sheep'/146, l='MpServer', x=-227.56, y=71.00, z=-186.66], EntityBat['Bat'/384, l='MpServer', x=-304.50, y=21.00, z=-174.50], EntityPig['Pig'/148, l='MpServer', x=-223.91, y=73.00, z=-302.88], EntitySheep['Sheep'/149, l='MpServer', x=-208.19, y=71.00, z=-269.72], EntitySheep['Sheep'/150, l='MpServer', x=-220.22, y=68.00, z=-248.25], EntitySheep['Sheep'/151, l='MpServer', x=-221.88, y=69.00, z=-233.88], EntityBat['Bat'/304, l='MpServer', x=-336.50, y=35.00, z=-156.50], EntityBat['Bat'/168, l='MpServer', x=-206.75, y=32.00, z=-155.50], EntitySheep['Sheep'/160, l='MpServer', x=-200.81, y=72.00, z=-286.81], EntityChicken['Chicken'/76, l='MpServer', x=-348.59, y=72.00, z=-276.59], EntityChicken['Chicken'/78, l='MpServer', x=-342.69, y=66.00, z=-257.47], EntitySheep['Sheep'/79, l='MpServer', x=-348.88, y=63.00, z=-248.94], EntityItem['item.item.egg'/87, l='MpServer', x=-334.78, y=71.13, z=-261.47], EntityBat['Bat'/86, l='MpServer', x=-332.25, y=15.09, z=-294.25], EntityCow['Cow'/93, l='MpServer', x=-324.91, y=63.00, z=-238.59], EntityCow['Cow'/92, l='MpServer', x=-324.91, y=63.00, z=-239.78], EntityCow['Cow'/95, l='MpServer', x=-324.91, y=63.00, z=-237.41], EntityCow['Cow'/94, l='MpServer', x=-324.91, y=63.00, z=-234.13], EntityCow['Cow'/89, l='MpServer', x=-323.75, y=63.00, z=-240.91], EntityCow['Cow'/88, l='MpServer', x=-324.91, y=63.00, z=-240.91], EntitySheep['Sheep'/91, l='MpServer', x=-335.19, y=63.00, z=-252.56], EntityCow['Cow'/90, l='MpServer', x=-320.50, y=63.00, z=-240.91], EntityCow['Cow'/102, l='MpServer', x=-322.63, y=63.00, z=-234.09], EntityCow['Cow'/103, l='MpServer', x=-323.66, y=63.00, z=-237.16], EntityItem['item.item.egg'/100, l='MpServer', x=-320.03, y=63.13, z=-225.34], EntityCow['Cow'/101, l='MpServer', x=-321.50, y=63.00, z=-239.03], EntityCow['Cow'/98, l='MpServer', x=-323.63, y=63.00, z=-235.41], EntityItem['item.item.dyePowder.black'/99, l='MpServer', x=-335.13, y=61.13, z=-236.41], EntityCow['Cow'/96, l='MpServer', x=-324.91, y=63.00, z=-235.44], EntityClientPlayerMP['ExodusDeath'/215, l='MpServer', x=-275.72, y=61.62, z=-223.47], EntityCow['Cow'/97, l='MpServer', x=-320.44, y=63.00, z=-234.88], EntityBat['Bat'/381, l='MpServer', x=-302.50, y=21.00, z=-176.50], EntityBat['Bat'/110, l='MpServer', x=-314.00, y=27.00, z=-262.63], EntityCow['Cow'/111, l='MpServer', x=-318.50, y=63.00, z=-240.91], EntityBat['Bat'/109, l='MpServer', x=-308.25, y=30.00, z=-261.63], EntitySheep['Sheep'/106, l='MpServer', x=-320.97, y=64.00, z=-149.06], EntitySheep['Sheep'/107, l='MpServer', x=-335.13, y=64.00, z=-148.91], EntityCow['Cow'/104, l='MpServer', x=-323.75, y=63.00, z=-239.75], EntityBat['Bat'/105, l='MpServer', x=-333.25, y=19.09, z=-148.25], EntityCow['Cow'/118, l='MpServer', x=-319.22, y=63.00, z=-235.13], EntityCow['Cow'/117, l='MpServer', x=-319.41, y=63.00, z=-236.88], EntityCow['Cow'/116, l='MpServer', x=-318.09, y=63.00, z=-234.09], EntityChicken['Chicken'/115, l='MpServer', x=-318.59, y=63.00, z=-224.53], EntityCow['Cow'/114, l='MpServer', x=-318.09, y=63.00, z=-236.25], EntityCow['Cow'/113, l='MpServer', x=-318.09, y=63.00, z=-239.59], EntityCow['Cow'/112, l='MpServer', x=-318.09, y=63.00, z=-237.47], EntityBat['Bat'/125, l='MpServer', x=-298.25, y=8.09, z=-160.25], EntityBat['Bat'/124, l='MpServer', x=-302.28, y=21.50, z=-179.75]]
Retry entities: 0 total; []
Stacktrace:
at net.minecraft.client.multiplayer.WorldClient.func_72914_a(WorldClient.java:441)
at net.minecraft.client.Minecraft.func_71396_d(Minecraft.java:2413)
at net.minecraft.client.Minecraft.run(Minecraft.java:782)
at java.lang.Thread.run(Unknown Source)

And then System

-- System Details --
Details:
Minecraft Version: 1.5.1
Operating System: Windows Vista (x86) version 6.0
Java Version: 1.7.0_21, Oracle Corporation
Java VM Version: Java HotSpot(TM) Client VM (mixed mode, sharing), Oracle Corporation
Memory: 123079736 bytes (117 MB) / 390766592 bytes (372 MB) up to 518979584 bytes (494 MB)
JVM Flags: 3 total; -XX:MaxPermSize=256m -Xms256m -Xmx512m
AABB Pool Size: 9359 (524104 bytes; 0 MB) allocated, 9359 (524104 bytes; 0 MB) used
Suspicious classes: FML and Forge are installed
IntCache: cache: 0, tcache: 0, allocated: 3, tallocated: 63
FML: MCP v7.44 FML v5.1.43.679 Minecraft Forge 7.7.2.679 68 mods loaded, 68 mods active
mcp{7.44} Minecraft Coder Pack Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
FML{5.1.43.679} Forge Mod Loader Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
Forge{7.7.2.679} Minecraft Forge Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
CodeChickenCore{0.8.6.3} CodeChicken Core Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
CoFHCore{1.5.1.2} CoFH Core Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
NotEnoughItems{1.5.2.10} Not Enough Items Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
PowerCrystalsCore{1.1.3} PowerCrystals Core Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
CoFHNetwork{1.5.1.2} CoFHNetwork Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
CoFHWorld{1.5.1.2} CoFHWorld Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
EnderTanks{1.5} [Ender Tanks]([1.5.1]EnderTanks v1.5.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
BasicComponents{1.3.2} Basic Components Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
BuildCraft|Core{3.5.0} BuildCraft Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
BuildCraft|Transport{3.5.0} BC Transport Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
BuildCraft|Silicon{3.5.0} BC Silicon Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
OmniTools{3.1.0.0} OmniTools Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
ThermalExpansion{2.3.2.0} [Thermal Expansion](ThermalExpansion-2.3.2.0 %281%29.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
IC2{1.115.304-lf} IndustrialCraft 2 Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
AppliedEnergistics{rv.10.h} [Applied Energistics](appeng-rv10-h %281%29.zip) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
AtomicScience{0.5.1} Atomic Science Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
Backpack{1.7.8} Backpack Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
BiblioCraft{1.1.6} BiblioCraft Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
BuildCraft|Builders{3.5.0} BC Builders Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
BuildCraft|Energy{3.5.0} BC Energy Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
BuildCraft|Factory{3.5.0} BC Factory Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
ChickenChunks{1.3.2.5} [ChickenChunks](ChickenChunks 1.3.2.5.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
ComputerCraft{1.52} ComputerCraft Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
CCTurtle{1.52} ComputerCraft Turtles Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
EE3{pre1g} Equivalent Exchange 3 Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
ElectricExpansion{2.1.0} Electric Expansion Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
EnderStorage{1.4.2.4} [EnderStorage](EnderStorage 1.4.2.4.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
factorization{0.7.37} Factorization Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
factorization.misc{0.7.37} Factorization Miscellaneous Nonsense Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
factorization.dimensionalSlice{0.7.37} Factorization Dimensional Slices Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
MineFactoryReloaded|CompatForestryPre{1.5.1R2.5.1} MFR Compat: Forestry (2) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
Forestry{2.2.0.0} Forestry for Minecraft Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
iChunUtil{1.0.0} iChunUtil Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
GraviGun{1.5.0.2} GraviGun Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
IronChest{5.2.4.383} Iron Chest Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
Mekanism{5.5.5} [Mekanism](Mekanism-v5.5.5.37 %281%29.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
MekanismGenerators{5.5.5} MekanismGenerators Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
MineFactoryReloaded{1.5.1R2.5.1} MineFactory Reloaded Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
MineFactoryReloaded|CompatAtum{1.5.1R2.5.1} MFR Compat: Atum Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
MineFactoryReloaded|CompatBiomesOPlenty{1.5.1R2.5.1} MFR Compat: Biomes O' Plenty Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
MineFactoryReloaded|CompatChococraft{1.5.1R2.5.1} MFR Compat: Chococraft Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
MineFactoryReloaded|CompatExtraBiomes{1.5.1R2.5.1} MFR Compat: ExtraBiomes Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
MineFactoryReloaded|CompatForestry{1.5.1R2.5.1} MFR Compat: Forestry Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
MineFactoryReloaded|CompatIC2{1.5.1R2.5.1} MFR Compat: IC2 Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
MineFactoryReloaded|CompatMagicalCrops{1.5.1R2.5.1} MFR Compat: Magical Crops Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
MineFactoryReloaded|CompatNatura{1.5.1R2.5.1} MFR Compat: Natura Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
MineFactoryReloaded|CompatPams{1.5.1R2.5.1} MFR Compat: Pam's Mods Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
MineFactoryReloaded|CompatRP2{1.5.1R2.5.1} MFR Compat: RP2 Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
MineFactoryReloaded|CompatSoulShards{1.5.1R2.5.1} MFR Compat: SoulShards Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
MineFactoryReloaded|CompatSufficientBiomes{1.5.1R2.5.1} MFR Compat: Sufficient Biomes Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
Thaumcraft{3.0.4c} Thaumcraft Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
MFReloaded|CompatThaumcraft{1.5.1R2.5.1} MFR Compat: Thaumcraft Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
TConstruct{1.5.1_1.2f2.1} Tinkers' Construct Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
MineFactoryReloaded|CompatTConstruct{1.5.1R2.5.1} MFR Compat: TConstruct Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
MineFactoryReloaded|CompatTwilightForest{1.5.1R2.5.1} MFR Compat: TwilightForest Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
MineFactoryReloaded|CompatVanilla{1.5.1R2.5.1} MFR Compat: Vanilla Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
MineFactoryReloaded|CompatXyCraft{1.5.1R2.5.1} MFR Compat: XyCraft Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
mmmPowersuits{0.6.0-444} MachineMuse's Modular Powersuits Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
PowersuitAddons{0.2.3-110} Andrew2448's Modular Powersuits Addon Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
Mystcraft{0.10.3.00} Mystcraft Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
NEIPlugins{1.0.6.2} NEI Plugins Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
PortalGun{1.5.1} PortalGun Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
Railcraft{6.17.0.34} Railcraft Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
PowerConverters{1.5.1R2.3.0} Power Converters Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
StevesCarts{2.0.0.a103} Steve's Carts Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
LWJGL: 2.9.0
OpenGL: ATI Radeon HD 2400 Series GL version 3.3.11653 Compatibility Profile Context, ATI Technologies Inc.
Is Modded: Definitely; Client brand changed to 'fml,forge'
Type: Client (map_client.txt)
Texture Pack: Default
Profiler Position: N/A (disabled)
Vec3 Pool Size: 28 (1568 bytes; 0 MB) allocated, 28 (1568 bytes; 0 MB) used

java.lang.NullPointerException
at net.minecraft.client.renderer.ItemRenderer.func_78446_a(ItemRenderer.java:605)
at net.minecraft.client.renderer.ItemRenderer.func_78447_b(ItemRenderer.java:556)
at net.minecraft.client.renderer.EntityRenderer.func_78476_b(EntityRenderer.java:705)
at net.minecraft.client.renderer.EntityRenderer.func_78471_a(EntityRenderer.java:1271)
at net.minecraft.client.renderer.EntityRenderer.func_78480_b(EntityRenderer.java:987)
at net.minecraft.client.Minecraft.func_71411_J(Minecraft.java:870)
at net.minecraft.client.Minecraft.run(Minecraft.java:759)
at java.lang.Thread.run(Unknown Source)
--- END ERROR REPORT 525f9ab4 ----------

Looks like a server/client config mismatch. Does no one read the readme for the bug tracker?