Hopper: java.lang.NullPointerException

java.lang.NullPointerException
	at va.e(SourceFile:199)
	at va.a(SourceFile:123)
	at vb.e(SourceFile:38)
	at mu.a(SourceFile:68)
	at we.c(SourceFile:77)
	at uy.a(SourceFile:465)
	at va.b(SourceFile:388)
	at uy.a(SourceFile:192)
	at bdc.a(SourceFile:295)
	at awy.a(SourceFile:582)
	at awy.a(SourceFile:410)
	at awz.a(SourceFile:121)
	at awe.d(SourceFile:128)
	at awe.m(SourceFile:107)

---- Minecraft Crash Report ----
// My bad.

Time: 19/09/13 17:06
Description: Updating screen events

java.lang.NullPointerException
	at va.e(SourceFile:199)
	at va.a(SourceFile:123)
	at vb.e(SourceFile:38)
	at mu.a(SourceFile:68)
	at we.c(SourceFile:77)
	at uy.a(SourceFile:465)
	at va.b(SourceFile:388)
	at uy.a(SourceFile:192)
	at bdc.a(SourceFile:295)
	at awy.a(SourceFile:582)
	at awy.a(SourceFile:410)
	at awz.a(SourceFile:121)
	at awe.d(SourceFile:128)
	at awe.m(SourceFile:107)
	at atv.k(SourceFile:1158)
	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 va.e(SourceFile:199)
	at va.a(SourceFile:123)
	at vb.e(SourceFile:38)
	at mu.a(SourceFile:68)
	at we.c(SourceFile:77)
	at uy.a(SourceFile:465)
	at va.b(SourceFile:388)
	at uy.a(SourceFile:192)
	at bdc.a(SourceFile:295)
	at awy.a(SourceFile:582)
	at awy.a(SourceFile:410)
	at awz.a(SourceFile:121)
	at awe.d(SourceFile:128)
	at awe.m(SourceFile:107)

-- Affected screen --
Details:
	Screen name: awz

-- Affected level --
Details:
	Level name: MpServer
	All players: 1 total; [bdi['markyf04'/21, l='MpServer', x=582.14, y=5.62, z=532.21]]
	Chunk stats: MultiplayerChunkCache: 441
	Level seed: 0
	Level generator: ID 01 - flat, ver 0. Features enabled: false
	Level generator options: 
	Level spawn location: World: (512,4,621), Chunk: (at 0,0,13 in 32,38; contains blocks 512,0,608 to 527,255,623), Region: (1,1; contains chunks 32,32 to 63,63, blocks 512,0,512 to 1023,255,1023)
	Level time: 469082 game time, 56893 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: creative (ID 1). Hardcore: false. Cheats: false
	Forced entities: 10 total; [od['entity.ItemFrame.name'/17, l='MpServer', x=582.94, y=5.50, z=537.50], od['entity.ItemFrame.name'/16, l='MpServer', x=582.94, y=5.50, z=535.50], od['entity.ItemFrame.name'/19, l='MpServer', x=582.94, y=5.50, z=533.50], od['entity.ItemFrame.name'/18, l='MpServer', x=582.94, y=5.50, z=538.50], bdi['markyf04'/21, l='MpServer', x=582.14, y=5.62, z=532.21], rs['Horse'/10, l='MpServer', x=524.97, y=4.88, z=539.00], su['entity.MinecartChest.name'/11, l='MpServer', x=515.50, y=2.97, z=546.50], su['entity.MinecartChest.name'/12, l='MpServer', x=515.50, y=2.97, z=546.50], od['entity.ItemFrame.name'/14, l='MpServer', x=582.94, y=5.50, z=536.50], od['entity.ItemFrame.name'/15, l='MpServer', x=582.94, y=5.50, z=535.50]]
	Retry entities: 0 total; []
	Server brand: vanilla
	Server type: Integrated singleplayer server
Stacktrace:
	at bdd.a(SourceFile:284)
	at atv.b(SourceFile:1761)
	at atv.d(SourceFile:628)
	at net.minecraft.client.main.Main.main(SourceFile:101)

-- System Details --
Details:
	Minecraft Version: 1.6.4
	Operating System: Windows XP (x86) version 5.1
	Java Version: 1.7.0_17, Oracle Corporation
	Java VM Version: Java HotSpot(TM) Client VM (mixed mode, sharing), Oracle Corporation
	Memory: 115560256 bytes (110 MB) / 365035520 bytes (348 MB) up to 518979584 bytes (494 MB)
	JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx512M
	AABB Pool Size: 9257 (518392 bytes; 0 MB) allocated, 3 (168 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: GeForce 6200 TurboCache(TM)/PCI/SSE2/3DNOW! GL version 2.0.0, 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: 203 (11368 bytes; 0 MB) allocated, 19 (1064 bytes; 0 MB) used