Hopper: java.lang.NullPointerException: Unexpected error

java.lang.NullPointerException: Unexpected error
	at ayz.k(SourceFile:129)
	at bkc.a(SourceFile:1098)
	at hz.a(SourceFile:43)
	at hz.a(SourceFile:9)
	at eg.a(SourceFile:166)
	at bkf.e(SourceFile:212)

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

Time: 26/02/14 20:38
Description: Unexpected error

java.lang.NullPointerException: Unexpected error
	at ayz.k(SourceFile:129)
	at bkc.a(SourceFile:1098)
	at hz.a(SourceFile:43)
	at hz.a(SourceFile:9)
	at eg.a(SourceFile:166)
	at bkf.e(SourceFile:212)
	at azl.p(SourceFile:1281)
	at azl.ah(SourceFile:757)
	at azl.f(SourceFile:711)
	at net.minecraft.client.main.Main.main(SourceFile:148)


A detailed walkthrough of the error, its code path and all known details is as follows:
---------------------------------------------------------------------------------------

-- Head --
Stacktrace:
	at ayz.k(SourceFile:129)
	at bkc.a(SourceFile:1098)
	at hz.a(SourceFile:43)
	at hz.a(SourceFile:9)
	at eg.a(SourceFile:166)
	at bkf.e(SourceFile:212)

-- Affected level --
Details:
	Level name: MpServer
	All players: 1 total; [bkl['Pipe_hard'/12970, l='MpServer', x=8,50, y=66,62, z=8,50]]
	Chunk stats: MultiplayerChunkCache: 0, 0
	Level seed: 0
	Level generator: ID 01 - flat, ver 0. Features enabled: false
	Level generator options: 
	Level spawn location: World: (-2134,77,522), Chunk: (at 10,4,10 in -134,32; contains blocks -2144,0,512 to -2129,255,527), Region: (-5,1; contains chunks -160,32 to -129,63, blocks -2560,0,512 to -2049,255,1023)
	Level time: 0 game time, 0 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: survival (ID 0). Hardcore: false. Cheats: false
	Forced entities: 1 total; [bkl['Pipe_hard'/12970, l='MpServer', x=8,50, y=66,62, z=8,50]]
	Retry entities: 0 total; []
	Server brand: vanilla
	Server type: Non-integrated multiplayer server
Stacktrace:
	at bkg.a(SourceFile:289)
	at azl.b(SourceFile:1947)
	at azl.f(SourceFile:725)
	at net.minecraft.client.main.Main.main(SourceFile:148)

-- System Details --
Details:
	Minecraft Version: 1.7.5
	Operating System: Windows 7 (x86) version 6.1
	Java Version: 1.7.0_45, Oracle Corporation
	Java VM Version: Java HotSpot(TM) Client VM (mixed mode, sharing), Oracle Corporation
	Memory: 90366264 bytes (86 MB) / 139632640 bytes (133 MB) up to 518979584 bytes (494 MB)
	JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx512M
	AABB Pool Size: 0 (0 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
	IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
	Launched Version: 1.7.5
	LWJGL: 2.9.1
	OpenGL: GeForce GT 430/PCIe/SSE2 GL version 4.3.0, NVIDIA Corporation
	GL Caps: Using GL 1.3 multitexturing.
Using framebuffer objects because OpenGL 3.0 is supported and separate blending is supported.
Anisotropic filtering is supported and maximum anisotropy is 16.
Shaders are available because OpenGL 2.1 is supported.

	Is Modded: Probably not. Jar signature remains and client brand is untouched.
	Type: Client (map_client.txt)
	Resource Packs: [blocksmith hybrid v1.5 resource pack.zip, Paper-Cutout-1.7.zip]
	Current Language: Português (BR)
	Profiler Position: N/A (disabled)
	Vec3 Pool Size: 0 (0 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
	Anisotropic Filtering: Off (1)