Hopper: java.lang.NullPointerException (SourceFile:571)

This is an automatically generated report based from the following crash: http://hopper.minecraft.net/crashes/minecraft/MCX-2126/

Crash:

java.lang.NullPointerException
	at bct.a(SourceFile:571)
	at df.a(SourceFile:87)
	at cn.b(SourceFile:354)
	at bct.e(SourceFile:98)
	at bcv.c(SourceFile:71)

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

---- Minecraft Crash Report ----
// I'm sorry, Dave.

Time: 8/8/13 11:37 AM
Description: Ticking screen

java.lang.NullPointerException
	at bct.a(SourceFile:571)
	at df.a(SourceFile:87)
	at cn.b(SourceFile:354)
	at bct.e(SourceFile:98)
	at bcv.c(SourceFile:71)
	at ats.k(SourceFile:1173)
	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 bct.a(SourceFile:571)
	at df.a(SourceFile:87)
	at cn.b(SourceFile:354)
	at bct.e(SourceFile:98)
	at bcv.c(SourceFile:71)

-- Affected screen --
Details:
	Screen name: ~~ERROR~~ NullPointerException: null

-- Affected level --
Details:
	Level name: MpServer
	All players: 1 total; [bdf['gogfg'/235804, l='MpServer', x=-463.50, y=64.62, z=-600.50]]
	Chunk stats: MultiplayerChunkCache: 10
	Level seed: 0
	Level generator: ID 00 - default, ver 1. Features enabled: false
	Level generator options: 
	Level spawn location: World: (-457,64,-596), Chunk: (at 7,4,12 in -29,-38; contains blocks -464,0,-608 to -449,255,-593), Region: (-1,-2; contains chunks -32,-64 to -1,-33, blocks -512,0,-1024 to -1,255,-513)
	Level time: 100770 game time, 100770 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: 1 total; [bdf['gogfg'/235804, l='MpServer', x=-463.50, y=64.62, z=-600.50]]
	Retry entities: 0 total; []
	Server brand: vanilla
	Server type: Non-integrated multiplayer server
Stacktrace:
	at bda.a(SourceFile:284)
	at ats.b(SourceFile:1761)
	at ats.d(SourceFile:628)
	at net.minecraft.client.main.Main.main(SourceFile:101)

-- System Details --
Details:
	Minecraft Version: 1.6.2
	Operating System: Mac OS X (x86_64) version 10.6.8
	Java Version: 1.6.0_43, Apple Inc.
	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Apple Inc.
	Memory: 52002104 bytes (49 MB) / 93814784 bytes (89 MB) up to 1065025536 bytes (1015 MB)
	JVM Flags: 1 total; -Xmx1G
	AABB Pool Size: 10817 (605752 bytes; 0 MB) allocated, 10817 (605752 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: Intel HD Graphics 3000 OpenGL Engine GL version 2.1 APPLE-1.6.42, Intel 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: 0 (0 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used

You can see this full report at http://hopper.minecraft.net/crashes/minecraft/MCX-2126/1399873/