Trying to access a family member's inventory after adding a number of items to it crashes the client.

Other family members' inventories are unaffected at first, but also crash the client when accessed a second time.

Minecraft 1.7.2 / MCA 4.0.1 / JRE 1.7.0u51 x64

---- Minecraft Crash Report ----
// Don't be sad, have a hug! <3

Time: 15/04/14 02:45
Description: Unexpected error

java.lang.NullPointerException: Unexpected error
at mca.core.MCA.getPlayerByName(MCA.java:925)
at mca.inventory.Inventory.onInventoryChanged(Inventory.java:293)
at mca.inventory.Inventory.func_70299_a(Inventory.java:238)
at net.minecraft.inventory.Slot.func_75215_d(Slot.java:77)
at net.minecraft.inventory.Container.func_75131_a(SourceFile:390)
at net.minecraft.client.network.NetHandlerPlayClient.func_147241_a(NetHandlerPlayClient.java:1044)
at net.minecraft.network.play.server.S30PacketWindowItems.func_148833_a(SourceFile:49)
at net.minecraft.network.play.server.S30PacketWindowItems.func_148833_a(SourceFile:11)
at net.minecraft.network.NetworkManager.func_74428_b(NetworkManager.java:197)
at net.minecraft.client.multiplayer.PlayerControllerMP.func_78765_e(PlayerControllerMP.java:273)
at net.minecraft.client.Minecraft.func_71407_l(Minecraft.java:1539)
at net.minecraft.client.Minecraft.func_71411_J(Minecraft.java:914)
at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:833)
at net.minecraft.client.main.Main.main(SourceFile:103)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at net.minecraft.launchwrapper.Launch.launch(Launch.java:134)
at net.minecraft.launchwrapper.Launch.main(Launch.java:28)

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

-- Head --
Stacktrace:
at mca.core.MCA.getPlayerByName(MCA.java:925)
at mca.inventory.Inventory.onInventoryChanged(Inventory.java:293)
at mca.inventory.Inventory.func_70299_a(Inventory.java:238)
at net.minecraft.inventory.Slot.func_75215_d(Slot.java:77)
at net.minecraft.inventory.Container.func_75131_a(SourceFile:390)
at net.minecraft.client.network.NetHandlerPlayClient.func_147241_a(NetHandlerPlayClient.java:1044)
at net.minecraft.network.play.server.S30PacketWindowItems.func_148833_a(SourceFile:49)
at net.minecraft.network.play.server.S30PacketWindowItems.func_148833_a(SourceFile:11)
at net.minecraft.network.NetworkManager.func_74428_b(NetworkManager.java:197)
at net.minecraft.client.multiplayer.PlayerControllerMP.func_78765_e(PlayerControllerMP.java:273)

-- Affected level --
Details:
Level name: MpServer
All players: 2 total; [EntityClientPlayerMP['player1'/126000, l='MpServer', x=1584.94, y=72.62, z=156.44], EntityOtherPlayerMP['player2'/81771, l='MpServer', x=1592.50, y=71.00, z=157.88]]
Chunk stats: MultiplayerChunkCache: 373, 373
Level seed: 0
Level generator: ID 00 - default, ver 1. Features enabled: false
Level generator options:
Level spawn location: World: (-220,64,256), Chunk: (at 4,4,0 in -14,16; contains blocks -224,0,256 to -209,255,271), Region: (-1,0; contains chunks -32,0 to -1,31, blocks -512,0,0 to -1,255,511)
Level time: 5759611 game time, 6860146 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: 118 total; [EntityZombie['Zombie'/125959, l='MpServer', x=1515.50, y=15.00, z=127.50], EntityClientPlayerMP['player1'/126000, l='MpServer', x=1584.94, y=72.62, z=156.44], EntitySheep['Sheep'/64333, l='MpServer', x=1653.13, y=69.00, z=192.19], EntitySheep['Sheep'/64332, l='MpServer', x=1654.06, y=70.00, z=196.25], EntitySheep['Sheep'/64095, l='MpServer', x=1570.34, y=73.00, z=214.50], EntitySheep['Sheep'/64335, l='MpServer', x=1643.56, y=69.00, z=198.31], EntityOtherPlayerMP['player2'/81771, l='MpServer', x=1592.50, y=71.00, z=157.88], EntitySheep['Sheep'/64334, l='MpServer', x=1651.25, y=70.00, z=203.78], EntitySkeleton['Skeleton'/125547, l='MpServer', x=1584.50, y=36.00, z=84.50], EntityPlayerChild['entity.mca.EntityPlayerChild.name'/123096, l='MpServer', x=1583.91, y=71.00, z=156.31], EntitySheep['Sheep'/63111, l='MpServer', x=1637.44, y=68.00, z=234.34], EntitySkeleton['Skeleton'/125536, l='MpServer', x=1659.50, y=20.00, z=164.50], EntityZombie['Zombie'/125564, l='MpServer', x=1542.50, y=20.00, z=170.50], EntityCreeper['Creeper'/125807, l='MpServer', x=1520.50, y=59.00, z=197.50], EntitySkeleton['Skeleton'/125805, l='MpServer', x=1594.44, y=48.00, z=179.07], EntityZombie['Zombie'/125802, l='MpServer', x=1507.50, y=15.00, z=126.50], EntityVillagerAdult['entity.mca.EntityVillagerAdult.name'/107799, l='MpServer', x=1566.38, y=70.00, z=147.47], EntityItem['item.item.rottenFlesh'/124307, l='MpServer', x=1551.13, y=70.13, z=126.59], EntityItem['item.item.rottenFlesh'/125013, l='MpServer', x=1590.09, y=70.13, z=136.91], EntityBat['Bat'/125518, l='MpServer', x=1511.69, y=41.00, z=163.69], EntityZombie['Zombie'/125990, l='MpServer', x=1558.50, y=48.00, z=194.50], EntityBat['Bat'/125510, l='MpServer', x=1527.41, y=18.10, z=223.59], EntitySkeleton['Skeleton'/125999, l='MpServer', x=1507.50, y=17.00, z=132.50], EntityCreeper['Creeper'/125775, l='MpServer', x=1536.50, y=69.00, z=133.50], EntityBat['Bat'/126001, l='MpServer', x=1604.97, y=35.00, z=86.69], EntityBat['Bat'/126013, l='MpServer', x=1612.75, y=34.19, z=92.44], EntitySkeleton['Skeleton'/124547, l='MpServer', x=1507.50, y=72.00, z=96.50], EntityBat['Bat'/126014, l='MpServer', x=1602.75, y=37.00, z=90.03], EntityBat['Bat'/126015, l='MpServer', x=1606.66, y=36.38, z=86.00], EntityItem['item.item.string'/125525, l='MpServer', x=1573.59, y=71.13, z=105.09], EntitySheep['Sheep'/64097, l='MpServer', x=1599.28, y=71.00, z=206.78], EntitySheep['Sheep'/64096, l='MpServer', x=1562.06, y=70.00, z=123.47], EntitySpider['Spider'/125046, l='MpServer', x=1525.59, y=48.77, z=185.72], EntitySheep['Sheep'/64098, l='MpServer', x=1607.03, y=71.00, z=196.91], EntityBat['Bat'/126017, l='MpServer', x=1599.25, y=36.45, z=88.75], EntitySpider['Spider'/125208, l='MpServer', x=1595.50, y=71.00, z=203.53], EntityCreeper['Creeper'/126021, l='MpServer', x=1543.50, y=18.00, z=128.50], EntityZombie['Zombie'/125204, l='MpServer', x=1593.50, y=71.00, z=195.50], EntityBat['Bat'/125744, l='MpServer', x=1645.44, y=31.51, z=204.47], EntityItem['item.item.rottenFlesh'/123578, l='MpServer', x=1579.66, y=71.13, z=108.06], EntitySkeleton['Skeleton'/126030, l='MpServer', x=1629.44, y=38.00, z=89.06], EntityBat['Bat'/125741, l='MpServer', x=1656.50, y=28.66, z=195.47], EntityItem['item.item.carrots'/124651, l='MpServer', x=1591.81, y=71.13, z=162.88], EntityVillagerAdult['entity.mca.EntityVillagerAdult.name'/64891, l='MpServer', x=1592.50, y=71.00, z=154.50], EntityItem['item.item.rottenFlesh'/124372, l='MpServer', x=1558.97, y=70.13, z=123.56], EntityWaypointContainer['unknown'/98, l='MpServer', x=0.00, y=0.00, z=0.00], EntitySpider['Spider'/124391, l='MpServer', x=1526.91, y=69.00, z=161.97], EntityZombie['Zombie'/126069, l='MpServer', x=1554.50, y=47.00, z=100.50], EntityZombie['Zombie'/126075, l='MpServer', x=1624.50, y=37.00, z=107.50], EntitySpider['Spider'/126078, l='MpServer', x=1575.50, y=15.00, z=89.50], EntityCreeper['Creeper'/126079, l='MpServer', x=1560.50, y=53.00, z=132.50], EntityCreeper['Creeper'/126088, l='MpServer', x=1567.50, y=70.00, z=198.50], EntityCreeper['Creeper'/126089, l='MpServer', x=1565.50, y=70.00, z=198.50], EntitySpider['Spider'/126082, l='MpServer', x=1536.50, y=29.00, z=220.50], EntityItem['item.item.rottenFlesh'/125133, l='MpServer', x=1602.06, y=70.13, z=130.06], EntitySheep['Sheep'/64471, l='MpServer', x=1539.91, y=69.00, z=184.94], EntityZombie['Zombie'/125934, l='MpServer', x=1524.50, y=37.00, z=85.50], EntityVillagerAdult['entity.mca.EntityVillagerAdult.name'/64473, l='MpServer', x=1565.47, y=71.00, z=155.09], EntityVillagerAdult['entity.mca.EntityVillagerAdult.name'/90100, l='MpServer', x=1581.69, y=70.00, z=137.00], EntityVillagerAdult['entity.mca.EntityVillagerAdult.name'/95800, l='MpServer', x=1573.09, y=71.00, z=144.59], EntityItem['item.item.seeds'/125153, l='MpServer', x=1548.16, y=88.13, z=212.63], EntityVillagerAdult['entity.mca.EntityVillagerAdult.name'/95803, l='MpServer', x=1564.34, y=71.00, z=155.63], EntityVillagerAdult['entity.mca.EntityVillagerAdult.name'/95802, l='MpServer', x=1567.16, y=71.00, z=156.28], EntitySheep['Sheep'/63940, l='MpServer', x=1566.34, y=80.00, z=215.53], EntitySheep['Sheep'/63941, l='MpServer', x=1570.53, y=70.00, z=201.81], EntityVillagerAdult['entity.mca.EntityVillagerAdult.name'/95804, l='MpServer', x=1567.13, y=71.00, z=157.34], EntitySheep['Sheep'/63942, l='MpServer', x=1608.06, y=70.00, z=215.06], EntityBat['Bat'/125907, l='MpServer', x=1528.84, y=61.00, z=204.25], EntitySheep['Sheep'/63943, l='MpServer', x=1612.88, y=71.00, z=196.13], EntityVillagerAdult['entity.mca.EntityVillagerAdult.name'/95806, l='MpServer', x=1602.22, y=70.00, z=131.97], EntityVillagerAdult['entity.mca.EntityVillagerAdult.name'/95793, l='MpServer', x=1565.97, y=70.00, z=144.59], EntitySheep['Sheep'/95795, l='MpServer', x=1581.78, y=71.00, z=103.75], EntityVillagerAdult['entity.mca.EntityVillagerAdult.name'/95794, l='MpServer', x=1566.34, y=71.00, z=156.88], EntityVillagerAdult['entity.mca.EntityVillagerAdult.name'/95797, l='MpServer', x=1567.00, y=71.00, z=154.59], EntitySheep['Sheep'/95796, l='MpServer', x=1588.19, y=72.00, z=103.19], EntityCreeper['Creeper'/125640, l='MpServer', x=1508.50, y=65.00, z=223.50], EntityVillagerAdult['entity.mca.EntityVillagerAdult.name'/95799, l='MpServer', x=1578.50, y=71.00, z=108.50], EntityVillagerAdult['entity.mca.EntityVillagerAdult.name'/95798, l='MpServer', x=1578.31, y=71.00, z=152.78], EntityCreeper['Creeper'/125895, l='MpServer', x=1505.50, y=17.00, z=128.50], EntityCreeper['Creeper'/125888, l='MpServer', x=1519.50, y=68.00, z=170.97], EntityCreeper['Creeper'/125889, l='MpServer', x=1525.25, y=68.00, z=183.13], EntityZombie['Zombie'/125900, l='MpServer', x=1655.50, y=69.00, z=220.50], EntityBat['Bat'/117162, l='MpServer', x=1575.75, y=62.10, z=132.25], EntityWitch['Witch'/125601, l='MpServer', x=1613.88, y=30.00, z=113.50], EntitySheep['Sheep'/63668, l='MpServer', x=1636.84, y=69.00, z=219.94], EntitySheep['Sheep'/63666, l='MpServer', x=1605.09, y=72.00, z=189.25], EntityZombie['Zombie'/125341, l='MpServer', x=1658.50, y=37.00, z=198.50], EntityItem['item.item.rottenFlesh'/125885, l='MpServer', x=1585.38, y=71.13, z=111.19], EntitySkeleton['Skeleton'/125884, l='MpServer', x=1647.50, y=31.00, z=101.09], EntityCreeper['Creeper'/125617, l='MpServer', x=1641.50, y=45.00, z=147.50], EntitySkeleton['Skeleton'/125858, l='MpServer', x=1639.13, y=68.00, z=223.72], EntitySheep['Sheep'/63654, l='MpServer', x=1611.03, y=69.00, z=231.91], EntitySkeleton['Skeleton'/125862, l='MpServer', x=1630.50, y=68.00, z=228.50], EntitySkeleton['Skeleton'/125863, l='MpServer', x=1623.78, y=69.00, z=222.84], EntityItem['item.item.carrots'/124515, l='MpServer', x=1593.53, y=72.13, z=167.44], EntityZombie['Zombie'/125623, l='MpServer', x=1549.56, y=21.00, z=117.28], EntityItem['item.item.string'/123972, l='MpServer', x=1568.09, y=70.13, z=131.38], EntityItem['item.item.carrots'/124514, l='MpServer', x=1592.84, y=72.13, z=169.38], EntityZombie['Zombie'/125622, l='MpServer', x=1544.00, y=21.00, z=123.44], EntitySkeleton['Skeleton'/125625, l='MpServer', x=1544.50, y=21.00, z=108.50], EntitySkeleton['Skeleton'/125624, l='MpServer', x=1545.50, y=21.00, z=109.50], EntityEnderman['Enderman'/125870, l='MpServer', x=1509.06, y=36.00, z=188.69], EntitySheep['Sheep'/63656, l='MpServer', x=1598.84, y=70.00, z=233.84], EntityCreeper['Creeper'/125868, l='MpServer', x=1508.72, y=32.00, z=180.88], EntityCreeper['Creeper'/125869, l='MpServer', x=1506.97, y=37.00, z=189.41], EntitySpider['Spider'/125840, l='MpServer', x=1611.03, y=70.00, z=156.75], EntityItem['item.item.rottenFlesh'/125848, l='MpServer', x=1586.31, y=71.13, z=101.13], EntityMinecartChest['entity.MinecartChest.name'/63644, l='MpServer', x=1565.50, y=19.34, z=234.47], EntityCreeper['Creeper'/125824, l='MpServer', x=1506.50, y=12.00, z=158.50], EntityBat['Bat'/116498, l='MpServer', x=1580.75, y=57.10, z=131.59], EntityOtherPlayerMP['player2'/81771, l='MpServer', x=1592.50, y=71.00, z=157.88], EntitySkeleton['Skeleton'/125830, l='MpServer', x=1529.50, y=71.00, z=101.84], EntityZombie['Zombie'/125345, l='MpServer', x=1560.50, y=38.00, z=86.50], EntitySheep['Sheep'/63100, l='MpServer', x=1588.53, y=71.00, z=214.81], EntityVillagerAdult['entity.mca.EntityVillagerAdult.name'/82780, l='MpServer', x=1580.73, y=71.00, z=112.69], EntityZombie['Zombie'/125835, l='MpServer', x=1638.50, y=45.00, z=150.50], EntityEnderman['Enderman'/125597, l='MpServer', x=1624.31, y=28.00, z=117.91], EntitySpider['Spider'/125838, l='MpServer', x=1618.34, y=70.00, z=159.97]]
Retry entities: 0 total; []
Server brand: fml,forge
Stacktrace:
at net.minecraft.client.multiplayer.WorldClient.func_72914_a(WorldClient.java:368)
at net.minecraft.client.Minecraft.func_71396_d(Minecraft.java:2380)
at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:862)
at net.minecraft.client.main.Main.main(SourceFile:103)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at net.minecraft.launchwrapper.Launch.launch(Launch.java:134)
at net.minecraft.launchwrapper.Launch.main(Launch.java:28)

-- System Details --
Details:
Minecraft Version: 1.7.2
Operating System: Windows 7 (amd64) version 6.1
Java Version: 1.7.0_51, Oracle Corporation
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
Memory: 377783328 bytes (360 MB) / 714080256 bytes (681 MB) up to 954728448 bytes (910 MB)
JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx1G
AABB Pool Size: 15154 (848624 bytes; 0 MB) allocated, 3 (168 bytes; 0 MB) used
IntCache: cache: 0, tcache: 0, allocated: 13, tallocated: 95
FML: MCP v9.01-pre FML v7.2.156.1057 Minecraft Forge 10.12.0.1057 Optifine OptiFine_1.7.2_HD_U_D1 18 mods loaded, 18 mods active
mcp{8.09} Minecraft Coder Pack Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available
FML{7.2.156.1057} Forge Mod Loader Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available
Forge{10.12.0.1057} Minecraft Forge Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available
DynamicLights{1.3.2} Dynamic Lights Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available
DynamicLights_onFire{1.0.4} Dynamic Lights Burning Entity Module Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available
DynamicLights_creepers{1.0.4} Dynamic Lights Creeper Module Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available
DynamicLights_dropItems{1.0.6} Dynamic Lights EntityItem Module Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available
DynamicLights_entityClasses{1.0.1} Dynamic Lights Entity Light Module Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available
DynamicLights_mobEquipment{1.0.4} Dynamic Lights Mob Equipment Light Module Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available
DynamicLights_flameArrows{1.0.0} Dynamic Lights Fiery Arrows Light Module Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available
DynamicLights_floodLights{1.0.0} Dynamic Lights Flood Light Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available
DynamicLights_otherPlayers{1.0.6} Dynamic Lights OtherPlayers Light Module Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available
DynamicLights_thePlayer{1.1.1} Dynamic Lights Player Light Module Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available
inventorytweaks{1.57-116} Inventory Tweaks Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available
radixcore{1.0.0} [RadixCore](RadixCore-1.0.0 MC-1.7.2.zip) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available
mca{4.0.1} [Minecraft Comes Alive](MCA-4.0.1 MC-1.7.2.zip) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available
cfm{3.2.9.2} §6MrCrayfish's Furniture Mod Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available
voxelmap{1.7.2} VoxelMap Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available
Launched Version: 1.7.2-Forge10.12.0.1057
LWJGL: 2.9.0
OpenGL: ATI Radeon HD 4800 Series GL version 3.3.11672 Compatibility Profile Context, ATI Technologies Inc.
Is Modded: Definitely; Client brand changed to 'fml,forge'
Type: Client (map_client.txt)
Resource Packs: [ChromaHills-64x_1.7_1.0.7.zip]
Current Language: English (US)
Profiler Position: N/A (disabled)
Vec3 Pool Size: 2263 (126728 bytes; 0 MB) allocated, 23 (1288 bytes; 0 MB) used
Anisotropic Filtering: On (8)

Fixed by commit cd934d8. Look for the fix in 4.0.2.