Minecraft crashes for some reason... i dont know why

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

Time: 10.07.13 17:28
Description: Exception in world tick

java.lang.NullPointerException
	at atg.k(SourceFile:129)
	at bct.a(SourceFile:1105)
	at fs.a(SourceFile:43)
	at cn.b(SourceFile:354)
	at bct.e(SourceFile:98)
	at bda.b(SourceFile:60)
	at ats.k(SourceFile:1386)
	at ats.S(SourceFile:663)
	at ats.d(SourceFile:619)
	at net.minecraft.client.main.Main.main(SourceFile:101)


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

-- Head --
Stacktrace:
	at atg.k(SourceFile:129)
	at bct.a(SourceFile:1105)
	at fs.a(SourceFile:43)
	at cn.b(SourceFile:354)
	at bct.e(SourceFile:98)

-- Affected level --
Details:
	Level name: MpServer
	All players: 1 total; [bdf['_ConQuerer_'/125844, l='MpServer', x=-227,10, y=65,58, z=-617,38]]
	Chunk stats: MultiplayerChunkCache: 625
	Level seed: 0
	Level generator: ID 00 - default, ver 1. Features enabled: false
	Level generator options: 
	Level spawn location: World: (144,64,256), Chunk: (at 0,4,0 in 9,16; contains blocks 144,0,256 to 159,255,271), Region: (0,0; contains chunks 0,0 to 31,31, blocks 0,0,0 to 511,255,511)
	Level time: 22642 game time, 22642 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: creative (ID 1). Hardcore: false. Cheats: false
	Forced entities: 4 total; [sb['Squid'/9713, l='MpServer', x=-198,91, y=62,53, z=-599,09], bdf['_ConQuerer_'/125844, l='MpServer', x=-227,10, y=65,58, z=-617,38], sb['Squid'/9714, l='MpServer', x=-187,69, y=58,53, z=-582,91], rn['Bat'/9808, l='MpServer', x=-205,39, y=24,64, z=-625,25]]
	Retry entities: 0 total; []
	Server brand: craftbukkit
	Server type: Non-integrated multiplayer server
Stacktrace:
	at bda.a(SourceFile:284)
	at ats.k(SourceFile:1393)
	at ats.S(SourceFile:663)
	at ats.d(SourceFile:619)
	at net.minecraft.client.main.Main.main(SourceFile:101)

-- Affected level --
Details:
	Level name: MpServer
	All players: 1 total; [bdf['_ConQuerer_'/125844, l='MpServer', x=-227,10, y=65,58, z=-617,38]]
	Chunk stats: MultiplayerChunkCache: 625
	Level seed: 0
	Level generator: ID 00 - default, ver 1. Features enabled: false
	Level generator options: 
	Level spawn location: World: (144,64,256), Chunk: (at 0,4,0 in 9,16; contains blocks 144,0,256 to 159,255,271), Region: (0,0; contains chunks 0,0 to 31,31, blocks 0,0,0 to 511,255,511)
	Level time: 22642 game time, 22642 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: creative (ID 1). Hardcore: false. Cheats: false
	Forced entities: 4 total; [sb['Squid'/9713, l='MpServer', x=-198,91, y=62,53, z=-599,09], bdf['_ConQuerer_'/125844, l='MpServer', x=-227,10, y=65,58, z=-617,38], sb['Squid'/9714, l='MpServer', x=-187,69, y=58,53, z=-582,91], rn['Bat'/9808, l='MpServer', x=-205,39, y=24,64, z=-625,25]]
	Retry entities: 0 total; []
	Server brand: craftbukkit
	Server type: Non-integrated multiplayer server

-- System Details --
Details:
	Minecraft Version: 1.6.2
	Operating System: Windows 7 (amd64) version 6.1
	Java Version: 1.8.0-ea, Oracle Corporation
	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
	Memory: 176674040 bytes (168 MB) / 318636032 bytes (303 MB) up to 954466304 bytes (910 MB)
	JVM Flags: 1 total; -Xmx1G
	AABB Pool Size: 39349 (2203544 bytes; 2 MB) allocated, 48 (2688 bytes; 0 MB) used
	Suspicious classes: No suspicious classes found.
	IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
	Launched Version: 1.6.2
	LWJGL: 2.9.0
	OpenGL: Radeon (TM) HD 6770M      GL version 4.1.10428 Compatibility Profile Context, ATI Technologies Inc.
	Is Modded: Probably not. Jar signature remains and client brand is untouched.
	Type: Client (map_client.txt)
	Resource Pack: Default
	Current Language: English (US)
	Profiler Position: N/A (disabled)
	Vec3 Pool Size: 2358 (132048 bytes; 0 MB) allocated, 171 (9576 bytes; 0 MB) used