Hopper: java.lang.NullPointerException: Rendering Block Entity

java.lang.NullPointerException: Rendering Block Entity
	at agn.a(SourceFile:122)
	at agn.d(SourceFile:252)
	at bpb.a(SourceFile:20)
	at bpb.a(SourceFile:15)
	at bpb.a(SourceFile:10)

---- Minecraft Crash Report ----
// Shall we play a game?

Time: 10-1-14 20:11
Description: Rendering Block Entity

java.lang.NullPointerException: Rendering Block Entity
	at agn.a(SourceFile:122)
	at agn.d(SourceFile:252)
	at bpb.a(SourceFile:20)
	at bpb.a(SourceFile:15)
	at bpb.a(SourceFile:10)
	at bow.a(SourceFile:104)
	at bow.a(SourceFile:96)
	at bom.a(SourceFile:389)
	at bof.a(SourceFile:1080)
	at bof.b(SourceFile:875)
	at bax.ah(SourceFile:791)
	at bax.f(SourceFile:718)
	at net.minecraft.client.main.Main.main(SourceFile:154)


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

-- Head --
Stacktrace:
	at agn.a(SourceFile:122)
	at agn.d(SourceFile:252)
	at bpb.a(SourceFile:20)
	at bpb.a(SourceFile:15)
	at bpb.a(SourceFile:10)

-- Block Entity Details --
Details:
	Name: MobSpawner // apn
	Block type: ID #52 (tile.mobSpawner // aly)
	Block data value: 0 / 0x0 / 0b0000
	Block location: World: (-711,81,530), Chunk: (at 9,5,2 in -45,33; contains blocks -720,0,528 to -705,255,543), Region: (-2,1; contains chunks -64,32 to -33,63, blocks -1024,0,512 to -513,255,1023)
	Actual block type: ID #52 (tile.mobSpawner // aly)
	Actual block data value: 0 / 0x0 / 0b0000
Stacktrace:
	at bow.a(SourceFile:104)
	at bow.a(SourceFile:96)
	at bom.a(SourceFile:389)
	at bof.a(SourceFile:1080)

-- Affected level --
Details:
	Level name: MpServer
	All players: 1 total; [blv['FinnT730'/328, l='MpServer', x=-712,66, y=80,18, z=532,14]]
	Chunk stats: MultiplayerChunkCache: 225, 225
	Level seed: 0
	Level generator: ID 02 - largeBiomes, ver 0. Features enabled: false
	Level generator options: 
	Level spawn location: -664,00,63,00,166,00 - World: (-664,63,166), Chunk: (at 8,3,6 in -42,10; contains blocks -672,0,160 to -657,255,175), Region: (-2,0; contains chunks -64,0 to -33,31, blocks -1024,0,0 to -513,255,511)
	Level time: 193778 game time, 23761 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: 25 total; [wa['Sheep'/3276, l='MpServer', x=-779,34, y=70,00, z=589,50], yd['Zombie'/232910, l='MpServer', x=-711,97, y=81,00, z=529,09], yd['Zombie'/230391, l='MpServer', x=-706,31, y=63,00, z=527,38], yd['Zombie'/230393, l='MpServer', x=-714,15, y=64,00, z=536,53], yd['Zombie'/227945, l='MpServer', x=-690,48, y=62,36, z=520,97], wa['Sheep'/337, l='MpServer', x=-740,19, y=75,00, z=548,69], wa['Sheep'/336, l='MpServer', x=-726,94, y=71,00, z=573,13], wa['Sheep'/334, l='MpServer', x=-679,97, y=63,00, z=540,13], wa['Sheep'/335, l='MpServer', x=-727,50, y=71,00, z=552,50], blv['FinnT730'/328, l='MpServer', x=-712,66, y=80,18, z=532,14], wa['Sheep'/329, l='MpServer', x=-762,41, y=76,00, z=461,78], wa['Sheep'/375, l='MpServer', x=-760,50, y=72,00, z=571,50], wa['Sheep'/377, l='MpServer', x=-762,50, y=72,00, z=572,19], wa['Sheep'/376, l='MpServer', x=-762,50, y=72,00, z=573,78], wa['Sheep'/378, l='MpServer', x=-762,50, y=72,00, z=575,50], wa['Sheep'/412, l='MpServer', x=-734,50, y=85,00, z=611,50], wd['Squid'/229039, l='MpServer', x=-674,25, y=51,19, z=480,03], wa['Sheep'/384, l='MpServer', x=-740,66, y=83,00, z=611,47], wa['Sheep'/444, l='MpServer', x=-784,84, y=85,00, z=512,47], wa['Sheep'/423, l='MpServer', x=-785,53, y=67,00, z=591,53], wa['Sheep'/422, l='MpServer', x=-784,31, y=67,00, z=590,81], wa['Sheep'/469, l='MpServer', x=-780,81, y=88,00, z=519,81], wa['Sheep'/455, l='MpServer', x=-785,63, y=88,00, z=529,53], wa['Sheep'/454, l='MpServer', x=-770,13, y=80,00, z=494,88], wa['Sheep'/453, l='MpServer', x=-787,47, y=90,00, z=501,63]]
	Retry entities: 0 total; []
	Server brand: vanilla
	Server type: Integrated singleplayer server
Stacktrace:
	at blq.a(SourceFile:298)
	at bax.b(SourceFile:2013)
	at bax.f(SourceFile:727)
	at net.minecraft.client.main.Main.main(SourceFile:154)

-- System Details --
Details:
	Minecraft Version: 14w02c
	Operating System: Windows 7 (x86) version 6.1
	Java Version: 1.6.0_31, Sun Microsystems Inc.
	Java VM Version: Java HotSpot(TM) Client VM (mixed mode), Sun Microsystems Inc.
	Memory: 113773160 bytes (108 MB) / 243912704 bytes (232 MB) up to 1037959168 bytes (989 MB)
	JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx1G
	IntCache: cache: 0, tcache: 0, allocated: 13, tallocated: 103
	Launched Version: 14w02c
	LWJGL: 2.9.1
	OpenGL: GeForce GT 240/PCIe/SSE2/3DNOW! GL version 3.3.0, 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: []
	Current Language: English (US)
	Profiler Position: N/A (disabled)
	Anisotropic Filtering: On (16)