Crashed multiple times (everytime I accessed inventory and hit esc.)

---- Minecraft Crash Report ----
// Hey, that tickles! Hehehe!

Time: 2/28/13 4:50 PM
Description: Unexpected error

java.lang.NoClassDefFoundError: aux
	at net.minecraft.client.Minecraft.l(Minecraft.java:1753)
	at net.minecraft.client.Minecraft.J(Minecraft.java:846)
	at net.minecraft.client.Minecraft.run(Minecraft.java:771)
	at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.ClassNotFoundException: aux
	at cpw.mods.fml.relauncher.RelaunchClassLoader.findClass(RelaunchClassLoader.java:185)
	at java.lang.ClassLoader.loadClass(Unknown Source)
	at java.lang.ClassLoader.loadClass(Unknown Source)
	... 4 more
Caused by: java.lang.NullPointerException
	at cpw.mods.fml.relauncher.RelaunchClassLoader.findClass(RelaunchClassLoader.java:174)
	... 6 more


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

-- Affected level --
Details:
	Level name: MpServer
	All players: 1 total; [ays['FarpFarp'/3771379, l='MpServer', x=3625.61, y=192.62, z=5225.46]]
	Chunk stats: MultiplayerChunkCache: 169
	Level seed: 0
	Level generator: ID 00 - default, ver 1. Features enabled: false
	Level generator options: 
	Level spawn location: World: (0,64,0), Chunk: (at 0,4,0 in 0,0; contains blocks 0,0,0 to 15,255,15), Region: (0,0; contains chunks 0,0 to 31,31, blocks 0,0,0 to 511,255,511)
	Level time: 92714171 game time, 92784537 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: 2 total; [ays['FarpFarp'/3771379, l='MpServer', x=3625.61, y=192.62, z=5225.46], px['item.tile.sapling.oak'/3782985, l='MpServer', x=3625.60, y=191.13, z=5225.43]]
	Retry entities: 0 total; []
Stacktrace:
	at ayp.a(WorldClient.java:440)
	at net.minecraft.client.Minecraft.b(Minecraft.java:2401)
	at net.minecraft.client.Minecraft.run(Minecraft.java:794)
	at java.lang.Thread.run(Unknown Source)

-- System Details --
Details:
	Minecraft Version: 1.4.7
	Operating System: Windows 8 (x86) version 6.2
	Java Version: 1.7.0_13, Oracle Corporation
	Java VM Version: Java HotSpot(TM) Client VM (mixed mode), Oracle Corporation
	Memory: 306978672 bytes (292 MB) / 519110656 bytes (495 MB) up to 1037959168 bytes (989 MB)
	JVM Flags: 2 total; -Xms512m -Xmx1024m
	AABB Pool Size: 52 (2912 bytes; 0 MB) allocated, 2 (112 bytes; 0 MB) used
	Suspicious classes: FML and Forge are installed
	IntCache: cache: 0, tcache: 0, allocated: 3, tallocated: 63
	FML: MCP v7.26 FML v4.7.4.520 Minecraft Forge 6.6.0.497 6 mods loaded, 6 mods active
	mcp [Minecraft Coder Pack] (minecraft.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available
	FML [Forge Mod Loader] (coremods) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available
	Forge [Minecraft Forge] (coremods) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available
	GuiAPI [GuiAPI] (GuiAPI-0.15.2-1.4.6.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available
	CustomSpawner [DrZhark's CustomSpawner] (CustomMobSpawner 1.11.zip) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available
	MoCreatures [DrZhark's Mo'Creatures Mod] (DrZharks MoCreatures Mod v4.5.1.zip) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available
	LWJGL: 2.4.2
	OpenGL: Intel(R) HD Graphics 4000 GL version 4.0.0 - Build 9.17.10.2828, Intel
	Is Modded: Definitely; Client brand changed to 'forge,fml'
	Type: Client (map_client.txt)
	Texture Pack: Default
	Profiler Position: N/A (disabled)
	Vec3 Pool Size: 56 (3136 bytes; 0 MB) allocated, 15 (840 bytes; 0 MB) used