Hopper: java.lang.NullPointerException bct.a(SourceFile:671)

This is an automatically generated report based from the following crash: http://hopper.minecraft.net/crashes/minecraft/MCX-14759/

Crash:

java.lang.NullPointerException
	at bct.a(SourceFile:671)
	at fg.a(SourceFile:28)
	at cn.b(SourceFile:354)
	at bct.e(SourceFile:98)
	at bdh.c(SourceFile:31)

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

---- Minecraft Crash Report ----
// I let you down. Sorry :(

Time: 8/15/13 12:11 PM
Description: Ticking screen

java.lang.NullPointerException
	at bct.a(SourceFile:671)
	at fg.a(SourceFile:28)
	at cn.b(SourceFile:354)
	at bct.e(SourceFile:98)
	at bdh.c(SourceFile:31)
	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:671)
	at fg.a(SourceFile:28)
	at cn.b(SourceFile:354)
	at bct.e(SourceFile:98)
	at bdh.c(SourceFile:31)

-- Affected screen --
Details:
	Screen name: bcx
Stacktrace:
	at ats.k(SourceFile:1173)
	at ats.S(SourceFile:663)
	at ats.d(SourceFile:619)
	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 10.7.5
	Java Version: 1.6.0_51, Apple Inc.
	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Apple Inc.
	Memory: 129932448 bytes (123 MB) / 192544768 bytes (183 MB) up to 1065025536 bytes (1015 MB)
	JVM Flags: 1 total; -Xmx1G
	AABB Pool Size: 6959 (389704 bytes; 0 MB) allocated, 2 (112 bytes; 0 MB) used
	Suspicious classes: No suspicious classes found.
	IntCache: cache: 0, tcache: 0, allocated: 3, tallocated: 63
	Launched Version: 1.6.2
	LWJGL: 2.9.0
	OpenGL: AMD Radeon HD 6750M OpenGL Engine GL version 2.1 ATI-7.32.12, 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 (UK)
	Profiler Position: N/A (disabled)
	Vec3 Pool Size: ~~ERROR~~ NullPointerException: null

You can see this full report at http://hopper.minecraft.net/crashes/minecraft/MCX-14759/3125308/