Hopper: java.lang.NullPointerException

java.lang.NullPointerException
	at nj.a(SourceFile:89)
	at of.aJ(SourceFile:384)
	at of.y(SourceFile:214)
	at nn.l_(SourceFile:278)
	at of.l_(SourceFile:1149)
	at uf.l_(SourceFile:203)
	at bdi.l_(SourceFile:46)
	at abw.a(SourceFile:1349)
	at abw.g(SourceFile:1327)

---- Minecraft Crash Report ----
// Oops.

Time: 19.09.13 18:13
Description: Ticking entity

java.lang.NullPointerException
	at nj.a(SourceFile:89)
	at of.aJ(SourceFile:384)
	at of.y(SourceFile:214)
	at nn.l_(SourceFile:278)
	at of.l_(SourceFile:1149)
	at uf.l_(SourceFile:203)
	at bdi.l_(SourceFile:46)
	at abw.a(SourceFile:1349)
	at abw.g(SourceFile:1327)
	at abw.h(SourceFile:1234)
	at atv.k(SourceFile:1380)
	at atv.S(SourceFile:663)
	at atv.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 nj.a(SourceFile:89)
	at of.aJ(SourceFile:384)
	at of.y(SourceFile:214)
	at nn.l_(SourceFile:278)
	at of.l_(SourceFile:1149)
	at uf.l_(SourceFile:203)
	at bdi.l_(SourceFile:46)
	at abw.a(SourceFile:1349)
	at abw.g(SourceFile:1327)

-- Entity being ticked --
Details:
	Entity Type: null (bdi)
	Entity ID: 1984
	Entity Name: maxdolgow
	Entity's Exact location: 17,85, 5,62, -7,40
	Entity's Block location: World: (17,5,-8), Chunk: (at 1,0,8 in 1,-1; contains blocks 16,0,-16 to 31,255,-1), Region: (0,-1; contains chunks 0,-32 to 31,-1, blocks 0,0,-512 to 511,255,-1)
	Entity's Momentum: 0,00, 0,00, 0,00
Stacktrace:
	at abw.h(SourceFile:1234)

-- Affected level --
Details:
	Level name: MpServer
	All players: 1 total; [bdi['maxdolgow'/1984, l='MpServer', x=17,85, y=5,62, z=-7,40]]
	Chunk stats: MultiplayerChunkCache: 0
	Level seed: 0
	Level generator: ID 02 - largeBiomes, ver 0. 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: 27927 game time, 27927 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: 1 total; [bdi['maxdolgow'/1984, l='MpServer', x=17,85, y=5,62, z=-7,40]]
	Retry entities: 0 total; []
	Server brand: vanilla
	Server type: Integrated singleplayer server
Stacktrace:
	at bdd.a(SourceFile:284)
	at atv.b(SourceFile:1761)
	at atv.d(SourceFile:628)
	at net.minecraft.client.main.Main.main(SourceFile:101)

-- System Details --
Details:
	Minecraft Version: 1.6.4
	Operating System: Windows 8 (x86) version 6.2
	Java Version: 1.7.0_25, Oracle Corporation
	Java VM Version: Java HotSpot(TM) Client VM (mixed mode, sharing), Oracle Corporation
	Memory: 85895296 bytes (81 MB) / 207904768 bytes (198 MB) up to 518979584 bytes (494 MB)
	JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx512M
	AABB Pool Size: 18947 (1061032 bytes; 1 MB) allocated, 7 (392 bytes; 0 MB) used
	Suspicious classes: No suspicious classes found.
	IntCache: cache: 0, tcache: 0, allocated: 3, tallocated: 71
	Launched Version: 1.6.4
	LWJGL: 2.9.0
	OpenGL: GeForce GTX 660 Ti/PCIe/SSE2 GL version 4.3.0, NVIDIA Corporation
	Is Modded: Probably not. Jar signature remains and client brand is untouched.
	Type: Client (map_client.txt)
	Resource Pack: Default
	Current Language: Deutsch (Deutschland)
	Profiler Position: N/A (disabled)
	Vec3 Pool Size: 31 (1736 bytes; 0 MB) allocated, 27 (1512 bytes; 0 MB) used