I got this error whenever I my mob gets hurt, I have absolutely no idea what's going on can anybody help?

 

As can be seen in the crash report, all involved classes are vanilla classes... Can anybody tell me where to start searching for this bug?

 

 

---- Minecraft Crash Report ----
// I just don't know what went wrong 

Time: 06/07/13 17:41
Description: Unexpected error

java.lang.UnsupportedOperationException: Cannot modify readonly attribute
at net.minecraft.entity.ai.attributes.ReadonlyAttributeInstance.func_111121_a(SourceFile:54)
at net.minecraft.entity.passive.EntityAnimal.func_70097_a(SourceFile:122)
at net.minecraft.entity.player.EntityPlayer.func_71059_n(EntityPlayer.java:1381)
at net.minecraft.client.multiplayer.PlayerControllerMP.func_78764_a(PlayerControllerMP.java:460)
at net.minecraft.client.Minecraft.func_71402_c(Minecraft.java:1350)
at net.minecraft.client.Minecraft.func_71407_l(Minecraft.java:1839)
at net.minecraft.client.Minecraft.func_71411_J(Minecraft.java:894)
at net.minecraft.client.Minecraft.run(Minecraft.java:822)
at net.minecraft.client.main.Main.main(SourceFile:101)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at net.minecraft.launchwrapper.Launch.launch(Launch.java:57)
at net.minecraft.launchwrapper.Launch.main(Launch.java:18)


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

-- Head --
Stacktrace:
at net.minecraft.entity.ai.attributes.ReadonlyAttributeInstance.func_111121_a(SourceFile:54)
at net.minecraft.entity.passive.EntityAnimal.func_70097_a(SourceFile:122)
at net.minecraft.entity.player.EntityPlayer.func_71059_n(EntityPlayer.java:1381)
at net.minecraft.client.multiplayer.PlayerControllerMP.func_78764_a(PlayerControllerMP.java:460)
at net.minecraft.client.Minecraft.func_71402_c(Minecraft.java:1350)

-- Affected level --
Details:
Level name: MpServer
All players: 1 total; [EntityClientPlayerMP['Torojima'/7, l='MpServer', x=276.85, y=63.54, z=421.06]]
Chunk stats: MultiplayerChunkCache: 441
Level seed: 0
Level generator: ID 01 - flat, ver 0. Features enabled: false
Level generator options: 
Level spawn location: World: (254,4,620), Chunk: (at 14,0,12 in 15,38; contains blocks 240,0,608 to 255,255,623), Region: (0,1; contains chunks 0,32 to 31,63, blocks 0,0,512 to 511,255,1023)
Level time: 3407 game time, 3407 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: 9 total; [EntityPig['Pig'/3463, l='MpServer', x=227.50, y=62.00, z=469.50], EntityChocoboYellow['Yellow Chocobo'/4, l='MpServer', x=285.28, y=62.00, z=428.19], EntityChocoboYellow['Yellow Chocobo'/5, l='MpServer', x=279.06, y=62.00, z=420.47], EntityChocoboYellow['Yellow Chocobo'/6, l='MpServer', x=290.52, y=62.00, z=432.36], EntityClientPlayerMP['Torojima'/7, l='MpServer', x=276.85, y=63.54, z=421.06], EntityPig['Pig'/3466, l='MpServer', x=235.66, y=62.00, z=474.78], EntityPig['Pig'/3465, l='MpServer', x=232.50, y=62.00, z=469.50], EntityPig['Pig'/3464, l='MpServer', x=230.50, y=62.00, z=469.50], EntityItem['item.item.chocoboFeather'/35797, l='MpServer', x=297.28, y=62.13, z=432.09]]
Retry entities: 0 total; []
Stacktrace:
at net.minecraft.client.multiplayer.WorldClient.func_72914_a(WorldClient.java:446)
at net.minecraft.client.Minecraft.func_71396_d(Minecraft.java:2284)
at net.minecraft.client.Minecraft.run(Minecraft.java:847)
at net.minecraft.client.main.Main.main(SourceFile:101)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at net.minecraft.launchwrapper.Launch.launch(Launch.java:57)
at net.minecraft.launchwrapper.Launch.main(Launch.java:18)

-- System Details --
Details:
Minecraft Version: 1.6.1
Operating System: Mac OS X (x86_64) version 10.6.8
Java Version: 1.6.0_51, Apple Inc.
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Apple Inc.
Memory: 86865320 bytes (82 MB) / 332988416 bytes (317 MB) up to 1065025536 bytes (1015 MB)
JVM Flags: 1 total; -Xmx1G
AABB Pool Size: 1575 (88200 bytes; 0 MB) allocated, 3 (168 bytes; 0 MB) used
Suspicious classes: FML and Forge are installed
IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
FML: MCP v8.03 FML v6.1.34.771 Minecraft Forge 8.9.0.771 5 mods loaded, 5 mods active
mcp{7.51} [Minecraft Coder Pack] (minecraft.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
FML{6.1.34.771} [Forge Mod Loader] (coremods) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
Forge{8.9.0.771} [Minecraft Forge] (coremods) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
chococraft{2.9.1} [Torojima's ChocoCraft] (Archive.zip) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
buildhelper{0.2.1} [Torojima's Build Helper] (buildhelper_0.2.1.zip) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
Launched Version: Forge8.9.0.771
LWJGL: 2.9.0
OpenGL: NVIDIA GeForce GT 330M OpenGL Engine GL version 2.1 NVIDIA-1.6.40, NVIDIA Corporation
Is Modded: Definitely; Client brand changed to 'fml,forge'
Type: Client (map_client.txt)
Resource Pack: Default
Profiler Position: N/A (disabled)
Vec3 Pool Size: 370 (20720 bytes; 0 MB) allocated, 16 (896 bytes; 0 MB) used

 

I would go into the file mentioned and find line 54, and see what the fuck "func_111121_a" is doing.

Since you are working with an entity is it possible that you are trying to set a variable you don't have access to?

Maybe you are reducing it's current health by adjusting it's health value directly or something similar?

 

You could also try to run in debugg mode, get ready to dmg you're mob and tab to the IDE, set a breakpoint on the mentioned line and place, then dmg the mob and see how the code looks like when it hits the break point?

 

For me it seems that you are trying to change a value you aren't supposed to change, there may be a method you need to invoke instead of changing a variable directly or something to that effect?