Hopper: java.lang.NullPointerException at bct.a(SourceFile:474)

java.lang.NullPointerException
	at bct.a(SourceFile:474)
	at ea.a(SourceFile:27)
	at cn.b(SourceFile:354)
	at bct.e(SourceFile:98)
	at bda.b(SourceFile:60)

---- Minecraft Crash Report ----
// You're mean.

Time: 8/2/13 2:36 PM
Description: Exception in world tick

java.lang.NullPointerException
	at bct.a(SourceFile:474)
	at ea.a(SourceFile:27)
	at cn.b(SourceFile:354)
	at bct.e(SourceFile:98)
	at bda.b(SourceFile:60)
	at ats.k(SourceFile:1386)
	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:474)
	at ea.a(SourceFile:27)
	at cn.b(SourceFile:354)
	at bct.e(SourceFile:98)
	at bda.b(SourceFile:60)

-- Affected level --
Details:
	Problem: Level is null!
Stacktrace:
	at ats.k(SourceFile:1386)
	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: 102274864 bytes (97 MB) / 144928768 bytes (138 MB) up to 1065025536 bytes (1015 MB)
	JVM Flags: 1 total; -Xmx1G
	AABB Pool Size: 398 (22288 bytes; 0 MB) allocated, 52 (2912 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: NVIDIA GeForce GT 330M OpenGL Engine GL version 2.1 NVIDIA-7.32.12, NVIDIA Corporation
	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: ~~ERROR~~ NullPointerException: null