Hopper: java.lang.NullPointerException

java.lang.NullPointerException
	at bcw.a(SourceFile:598)
	at fx.a(SourceFile:38)
	at co.b(SourceFile:354)
	at bcw.e(SourceFile:98)
	at bcy.c(SourceFile:71)

---- Minecraft Crash Report ----
// There are four lights!

Time: 9/29/13 12:21 AM
Description: Ticking screen

java.lang.NullPointerException
	at bcw.a(SourceFile:598)
	at fx.a(SourceFile:38)
	at co.b(SourceFile:354)
	at bcw.e(SourceFile:98)
	at bcy.c(SourceFile:71)
	at atv.k(SourceFile:1173)
	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 bcw.a(SourceFile:598)
	at fx.a(SourceFile:38)
	at co.b(SourceFile:354)
	at bcw.e(SourceFile:98)
	at bcy.c(SourceFile:71)

-- Affected screen --
Details:
	Screen name: bda
Stacktrace:
	at atv.k(SourceFile:1173)
	at atv.S(SourceFile:663)
	at atv.d(SourceFile:619)
	at net.minecraft.client.main.Main.main(SourceFile:101)

-- System Details --
Details:
	Minecraft Version: 1.6.4
	Operating System: Mac OS X (x86_64) version 10.6.8
	Java Version: 1.6.0_51, Apple Inc.
	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Apple Inc.
	Memory: 97199520 bytes (92 MB) / 139653120 bytes (133 MB) up to 1037959168 bytes (989 MB)
	JVM Flags: 1 total; -Xmx1G
	AABB Pool Size: 0 (0 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
	Suspicious classes: No suspicious classes found.
	IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
	Launched Version: 1.6.4
	LWJGL: 2.9.0
	OpenGL: ATI Radeon HD 2600 PRO OpenGL Engine GL version 2.1 ATI-1.6.36, ATI Technologies Inc.
	Is Modded: Probably not. Jar signature remains and client brand is untouched.
	Type: Client (map_client.txt)
	Resource Pack: Sphax PureBDcraft  64x MC16.zip
	Current Language: English (US)
	Profiler Position: N/A (disabled)
	Vec3 Pool Size: ~~ERROR~~ NullPointerException: null