Hopper: java.lang.NullPointerException

java.lang.NullPointerException
	at bct.a(SourceFile:469)
	at gf.a(SourceFile:44)
	at cn.b(SourceFile:354)
	at bct.e(SourceFile:98)
	at bda.b(SourceFile:60)

---- Minecraft Crash Report ----
// Daisy, daisy...

Time: 8/6/13 5:59 PM
Description: Exception in world tick

java.lang.NullPointerException
	at bct.a(SourceFile:469)
	at gf.a(SourceFile:44)
	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:469)
	at gf.a(SourceFile:44)
	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: Windows XP (x86) version 5.1
	Java Version: 1.6.0_38, Sun Microsystems Inc.
	Java VM Version: Java HotSpot(TM) Client VM (mixed mode, sharing), Sun Microsystems Inc.
	Memory: 84770456 bytes (80 MB) / 145068032 bytes (138 MB) up to 518979584 bytes (494 MB)
	JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx512M
	AABB Pool Size: 7955 (445480 bytes; 0 MB) allocated, 549 (30744 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: GeForce 6150 LE/PCI/SSE2/3DNOW! GL version 2.0.1, 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