Hopper: java.lang.NullPointerException

This is an automatically generated report based from the following crash: http://hopper.minecraft.net/crashes/minecraft/MCX-83944/

Crash:

java.lang.NullPointerException
	at ny.f(SourceFile:108)
	at zj.n(SourceFile:184)
	at yx.s(SourceFile:363)
	at axb.a(SourceFile:209)

The following is the first clean report made public about this crash:

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

Time: 06-09-2013 14:49
Description: Unexpected error

java.lang.NullPointerException
	at ny.f(SourceFile:108)
	at zj.n(SourceFile:184)
	at yx.s(SourceFile:363)
	at axb.a(SourceFile:209)
	at bho.b(SourceFile:702)
	at awb.V(SourceFile:713)
	at awb.e(SourceFile:642)
	at net.minecraft.client.main.Main.main(SourceFile:103)


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

-- Head --
Stacktrace:
	at ny.f(SourceFile:108)
	at zj.n(SourceFile:184)
	at yx.s(SourceFile:363)
	at axb.a(SourceFile:209)

-- Affected level --
Details:
	Level name: MpServer
	All players: 1 total; [bfn['xH4rdStyl3zx'/2, l='MpServer', x=944,06, y=2,62, z=-477,82]]
	Chunk stats: MultiplayerChunkCache: 287, 287
	Level seed: 0
	Level generator: ID 01 - flat, ver 0. Features enabled: false
	Level generator options: 
	Level spawn location: World: (930,4,-453), Chunk: (at 2,0,11 in 58,-29; contains blocks 928,0,-464 to 943,255,-449), Region: (1,-1; contains chunks 32,-32 to 63,-1, blocks 512,0,-512 to 1023,255,-1)
	Level time: 43562 game time, 1000 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: 2 total; [bfn['xH4rdStyl3zx'/2, l='MpServer', x=944,06, y=2,62, z=-477,82], su['Wolf'/344, l='MpServer', x=925,82, y=1,00, z=-476,75]]
	Retry entities: 0 total; []
	Server brand: vanilla
	Server type: Integrated singleplayer server
Stacktrace:
	at bfi.a(SourceFile:285)
	at awb.b(SourceFile:1813)
	at awb.e(SourceFile:656)
	at net.minecraft.client.main.Main.main(SourceFile:103)

-- System Details --
Details:
	Minecraft Version: 13w36b
	Operating System: Linux (amd64) version 3.7.0-7-generic
	Java Version: 1.7.0_09, Oracle Corporation
	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
	Memory: 166245472 bytes (158 MB) / 479985664 bytes (457 MB) up to 954466304 bytes (910 MB)
	JVM Flags: 1 total; -Xmx1G
	AABB Pool Size: 33 (1848 bytes; 0 MB) allocated, 33 (1848 bytes; 0 MB) used
	IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
	Launched Version: 13w36b
	LWJGL: 2.9.0
	OpenGL: GeForce GT 430/PCIe/SSE2 GL version 4.3.0 NVIDIA 325.15, NVIDIA Corporation
	Is Modded: Probably not. Jar signature remains and client brand is untouched.
	Type: Client (map_client.txt)
	Resource Packs: []
	Current Language: English (US)
	Profiler Position: N/A (disabled)
	Vec3 Pool Size: 50 (2800 bytes; 0 MB) allocated, 50 (2800 bytes; 0 MB) used

You can see this full report at http://hopper.minecraft.net/crashes/minecraft/MCX-83944/8329877/