Forge: 10.13.4.1448
AW: ancientwarfare-2.4.106-beta-MC1.7.10-FULL

When attempting to place an NPC the client crashes with an "Internal Server Error". No error log is generated on the client as far as I can tell.

On the server, what I get is: https://gist.github.com/Sandriell/5aeeba718cff141e0fe9

I get the same sort of problem in singleplayer, with this crash report
AW: 2.4.106-beta-MC1.7.10-FULL
ONLY HAPPENS IN SURVIVAL MODE, NOT CREATIVE MOD
---- Minecraft Crash Report ----
// Don't be sad. I'll do better next time, I promise!

Time: 7/3/15 9:46 AM
Description: Ticking memory connection

java.lang.NullPointerException: Ticking memory connection
at net.minecraft.server.management.ItemInWorldManager.func_73085_a(Unknown Source)
at net.minecraft.network.NetHandlerPlayServer.func_147346_a(NetHandlerPlayServer.java:539)
at net.minecraft.network.play.client.C08PacketPlayerBlockPlacement.func_148833_a(SourceFile:60)
at net.minecraft.network.play.client.C08PacketPlayerBlockPlacement.func_148833_a(SourceFile:9)
at net.minecraft.network.NetworkManager.func_74428_b(NetworkManager.java:212)
at net.minecraft.network.NetworkSystem.func_151269_c(NetworkSystem.java:165)
at net.minecraft.server.MinecraftServer.func_71190_q(MinecraftServer.java:659)
at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:547)
at net.minecraft.server.integrated.IntegratedServer.func_71217_p(IntegratedServer.java:186)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:427)
at net.minecraft.server.MinecraftServer$2.run(MinecraftServer.java:685)

A detailed walkthrough of the error, its code path and all known details is as follows:

-- Head --
Stacktrace:
at net.minecraft.server.management.ItemInWorldManager.func_73085_a(Unknown Source)
at net.minecraft.network.NetHandlerPlayServer.func_147346_a(NetHandlerPlayServer.java:539)
at net.minecraft.network.play.client.C08PacketPlayerBlockPlacement.func_148833_a(SourceFile:60)
at net.minecraft.network.play.client.C08PacketPlayerBlockPlacement.func_148833_a(SourceFile:9)
at net.minecraft.network.NetworkManager.func_74428_b(NetworkManager.java:212)

-- Ticking connection --
Details:
Connection: net.minecraft.network.NetworkManager@31bb293f
Stacktrace:
at net.minecraft.network.NetworkSystem.func_151269_c(NetworkSystem.java:165)
at net.minecraft.server.MinecraftServer.func_71190_q(MinecraftServer.java:659)
at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:547)
at net.minecraft.server.integrated.IntegratedServer.func_71217_p(IntegratedServer.java:186)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:427)
at net.minecraft.server.MinecraftServer$2.run(MinecraftServer.java:685)

-- System Details --
Details:
Minecraft Version: 1.7.10
Operating System: Windows 8.1 (amd64) version 6.3
Java Version: 1.8.0_25, Oracle Corporation
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
Memory: 679922760 bytes (648 MB) / 2875371520 bytes (2742 MB) up to 5154013184 bytes (4915 MB)
Mod Pack: Unknown / None
LiteLoader Mods: 3 loaded mod(s)
- WorldEditCUI version 1.7.10_00
- VoxelMap version 1.2.3
- DaFlight version 2.4r4
LaunchWrapper: 49 active transformer(s)
- Transformer: cpw.mods.fml.common.asm.transformers.PatchingTransformer
- Transformer: optifine.OptiFineClassTransformer
- Transformer: cpw.mods.fml.common.asm.transformers.MarkerTransformer
- Transformer: cpw.mods.fml.common.asm.transformers.SideTransformer
- Transformer: cpw.mods.fml.common.asm.transformers.EventSubscriptionTransformer
- Transformer: net.minecraftforge.classloading.FluidIdTransformer
- Transformer: code.elix_x.coremods.avoidexplodingcreepers.core.AvoidExplodingCreepersTransformer
- Transformer: me.guichaguri.betterfps.BetterFpsTransformer
- Transformer: codechicken.lib.asm.ClassHeirachyManager
- Transformer: codechicken.core.asm.InterfaceDependancyTransformer
- Transformer: codechicken.core.asm.TweakTransformer
- Transformer: codechicken.core.asm.DelegatedTransformer
- Transformer: codechicken.core.asm.DefaultImplementationTransformer
- Transformer: atomicstryker.dynamiclights.common.DLTransformer
- Transformer: fastcraft.asm.FastCraftTransformer
- Transformer: invtweaks.forge.asm.ContainerTransformer
- Transformer: atomicstryker.multimine.common.fmlmagic.MMTransformer
- Transformer: codechicken.nei.asm.NEITransformer
- Transformer: brad16840.common.asm.ClassTransformer
- Transformer: com.mumfrey.liteloader.transformers.event.EventProxyTransformer
- Transformer: com.mumfrey.liteloader.launch.LiteLoaderTransformer
- Transformer: com.mumfrey.liteloader.client.transformers.CrashReportTransformer
- Transformer: cpw.mods.fml.common.asm.transformers.DeobfuscationTransformer
- Transformer: cpw.mods.fml.common.asm.transformers.AccessTransformer
- Transformer: net.minecraftforge.transformers.ForgeAccessTransformer
- Transformer: mods.battlegear2.coremod.transformers.BattlegearAccessTransformer
- Transformer: codechicken.core.asm.CodeChickenAccessTransformer
- Transformer: invtweaks.forge.asm.ITAccessTransformer
- Transformer: cpw.mods.fml.common.asm.transformers.ModAccessTransformer
- Transformer: cpw.mods.fml.common.asm.transformers.ItemStackTransformer
- Transformer: mods.battlegear2.coremod.transformers.EntityPlayerTransformer
- Transformer: mods.battlegear2.coremod.transformers.ModelBipedTransformer
- Transformer: mods.battlegear2.coremod.transformers.NetClientHandlerTransformer
- Transformer: mods.battlegear2.coremod.transformers.NetServerHandlerTransformer
- Transformer: mods.battlegear2.coremod.transformers.PlayerControllerMPTransformer
- Transformer: mods.battlegear2.coremod.transformers.ItemRendererTransformer
- Transformer: mods.battlegear2.coremod.transformers.MinecraftTransformer
- Transformer: mods.battlegear2.coremod.transformers.ItemStackTransformer
- Transformer: mods.battlegear2.coremod.transformers.ItemInWorldTransformer
- Transformer: mods.battlegear2.coremod.transformers.EntityAIControlledByPlayerTransformer
- Transformer: mods.battlegear2.coremod.transformers.EntityOtherPlayerMPTransformer
- Transformer: cpw.mods.fml.common.asm.transformers.TerminalTransformer
- Transformer: me.dags.daflightliteloader.minecraft.transformers.PlayerControllerTransformer
- Transformer: com.mumfrey.liteloader.client.transformers.LiteLoaderEventInjectionTransformer
- Transformer: me.dags.daflightliteloader.minecraft.transformers.PlayerTransformer
- Transformer: com.mumfrey.liteloader.client.transformers.MinecraftOverlayTransformer
- Transformer: com.mumfrey.liteloader.common.transformers.LiteLoaderPacketTransformer
- Transformer: com.thevoxelbox.voxelmap.litemod.VoxelMapTransformer
- Transformer: cpw.mods.fml.common.asm.transformers.ModAPITransformer
JVM Flags: 6 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx5G -XX:+UseConcMarkSweepGC -XX:+CMSIncrementalMode -XX:-UseAdaptiveSizePolicy -Xmn2G
AABB Pool Size: 0 (0 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
IntCache: cache: 0, tcache: 0, allocated: 56, tallocated: 89
FML: MCP v9.05 FML v7.10.99.99 Minecraft Forge 10.13.4.1448 Optifine OptiFine_1.7.10_HD_U_B8 63 mods loaded, 63 mods active
States: 'U' = Unloaded 'L' = Loaded 'C' = Constructed 'H' = Pre-initialized 'I' = Initialized 'J' = Post-initialized 'A' = Available 'D' = Disabled 'E' = Errored
UCHIJAAAA mcp{9.05} Minecraft Coder Pack
UCHIJAAAA FML{7.10.99.99} Forge Mod Loader
UCHIJAAAA Forge{10.13.4.1448} Minecraft Forge
UCHIJAAAA betterfps{1.0.0} BetterFps
UCHIJAAAA CodeChickenCore{1.0.7.46} CodeChicken Core
UCHIJAAAA ivtoolkit{IvToolkit} 1.0.4
UCHIJAAAA NotEnoughItems{1.0.5.110} Not Enough Items
UCHIJAAAA backpacks16840{3.0.1} [Backpacks!](zz-backpacks 1.7.10 - 3.0.2.jar)
UCHIJAAAA battlegear2{1.7.10} Mine & Blade Battlegear 2 - Bullseye
UCHIJAAAA simplecore{1.1.0} [SimpleCore API]([1.7.10] SimpleCore API v1.1.0.jar)
UCHIJAAAA fusion{1.6.0} [Fusion]([1.7.10] Fusion v1.6.0.jar)
UCHIJAAAA simpleores{1.6.0} [SimpleOres 2]([1.7.10] SimpleOres 2 v1.6.0.jar)
UCHIJAAAA bspkrsCore{6.15} bspkrsCore
UCHIJAAAA Treecapitator{1.7.10} Treecapitator
UCHIJAAAA advanceddispensers{1.1.3.1} Advanced Dispensers Mod
UCHIJAAAA AncientWarfare{2.4.106-beta-MC1.7.10} Ancient Warfare Core
UCHIJAAAA AncientWarfareAutomation{2.4.106-beta-MC1.7.10} Ancient Warfare Automation
UCHIJAAAA AncientWarfareNEIPlugin{2.4.106-beta-MC1.7.10} Ancient Warfare NEI Plugin
UCHIJAAAA AncientWarfareNpc{2.4.106-beta-MC1.7.10} Ancient Warfare NPCs
UCHIJAAAA AncientWarfareStructure{2.4.106-beta-MC1.7.10} Ancient Warfare Structures
UCHIJAAAA MovingWorld{1.7.10-1.7.12B} Moving World
UCHIJAAAA ArchimedesShipsPlus{1.7.10-1.7.12} Archimedes' Ships Plus
UCHIJAAAA armorsets{1.0} Armor sets mod
UCHIJAAAA avoidexplodingcreepers{1.1} Avoid Exploding Creepers
UCHIJAAAA bettervanilla{1.1.1} BetterVanilla
UCHIJAAAA ChestTransporter{2.0.0} Chest Transporter
UCHIJAAAA climatecontrol{0.2} Climate Control
UCHIJAAAA Crowns{1.2} Crowns
UCHIJAAAA lootablebodies{1.3.5} DrCyano's Lootable Bodies
UCHIJAAAA DynamicLights{1.3.5} Dynamic Lights
UCHIJAAAA DynamicLights_dropItems{1.0.7} Dynamic Lights EntityItem Module
UCHIJAAAA DynamicLights_otherPlayers{1.0.7} Dynamic Lights OtherPlayers Light Module
UCHIJAAAA DynamicLights_thePlayer{1.1.3} Dynamic Lights Player Light Module
UCHIJAAAA weaponmod{v1.14.3} Balkon's WeaponMod
UCHIJAAAA exparmory{1.3.4} Expanded Armory
UCHIJAAAA FastCraft{1.21} FastCraft
UCHIJAAAA GregsLighting{1.11.2} Greg's Lighting
UCHIJAAAA Growthcraft{2.1.0a} Growthcraft
UCHIJAAAA Growthcraft|Cellar{2.1.0a} Growthcraft Cellar
UCHIJAAAA Growthcraft|Apples{2.1.0} Growthcraft Apples
UCHIJAAAA Growthcraft|Grapes{2.1.0} Growthcraft Grapes
UCHIJAAAA Growthcraft|Hops{2.1.0} Growthcraft Hops
UCHIJAAAA hidenames{1.1.7} [Hide Names](Hide Names-1.7.10-1.1.8.jar)
UCHIJAAAA HoloInventory{1.9.0.108} HoloInventory
UCHIJAAAA inventorytweaks{1.58-147-645ca10} Inventory Tweaks
UCHIJAAAA LLadders{0.5.0} Luppii's Ladders
UCHIJAAAA MapWriter{2.1.2} MapWriter
UCHIJAAAA MemoryCleaner{1.0} Memory Cleaner
UCHIJAAAA AS_MultiMine{1.4.3} Multi Mine
UCHIJAAAA simplypaths{1.7.10-1.0.0} Simply Paths
UCHIJAAAA soundfilters{0.8_for_1.7.X} Sound Filters
UCHIJAAAA SteelIndustries{1.7.10-0.5c} Steel Industries
UCHIJAAAA telepads{1.7.10 v1} [Teleportation Pads](Telepads 1.7.10 v2.jar)
UCHIJAAAA TwilightForest{2.3.5} The Twilight Forest
UCHIJAAAA worldedit{6.0-beta-01} WorldEdit
UCHIJAAAA ForgeMultipart{1.1.0.309} Forge Multipart
UCHIJAAAA WR-CBE|Core{1.4.1.9} WR-CBE Core
UCHIJAAAA WR-CBE|Addons{1.4.1.9} WR-CBE Addons
UCHIJAAAA WR-CBE|Logic{1.4.1.9} WR-CBE Logic
UCHIJAAAA YAFM{1.0.3} Yet Another Food Mod
UCHIJAAAA yegamolchattels{1.1.2} Ye Gamol Chattels
UCHIJAAAA McMultipart{1.1.0.309} Minecraft Multipart Plugin
UCHIJAAAA ForgeMicroblock{1.1.0.309} Forge Microblocks
Profiler Position: N/A (disabled)
Vec3 Pool Size: 0 (0 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
Player Count: 1 / 8; [EntityPlayerMP['ThatPolishKid99'/10150, l='Test1', x=902.72, y=77.00, z=820.08]]
Type: Integrated Server (map_client.txt)
Is Modded: Definitely; Client brand changed to 'fml,forge'