Exception ticking world

java.lang.NullPointerException: Exception ticking world
	at auc.a(SourceFile:36)
	at atu.a(SourceFile:88)
	at apl.a(SourceFile:132)
	at ml.a(SourceFile:160)
	at aoo.a(SourceFile:772)
	at ml.c(SourceFile:95)
	at ml.d(SourceFile:108)
	at afs.e(SourceFile:311)
	at mm.g(SourceFile:234)
	at mm.b(SourceFile:137)
	at net.minecraft.server.MinecraftServer.u(SourceFile:502)
	at net.minecraft.server.MinecraftServer.t(SourceFile:440)
	at btk.t(SourceFile:117)
	at net.minecraft.server.MinecraftServer.run(SourceFile:357)
	at lb.run(SourceFile:616)


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

-- Head --
Stacktrace:
	at auc.a(SourceFile:36)
	at atu.a(SourceFile:88)
	at apl.a(SourceFile:132)
	at ml.a(SourceFile:160)
	at aoo.a(SourceFile:772)
	at ml.c(SourceFile:95)
	at ml.d(SourceFile:108)
	at afs.e(SourceFile:311)
	at mm.g(SourceFile:234)
	at mm.b(SourceFile:137)

-- Affected level --
Details:
	Level name: Test world 2
	All players: 1 total; [mp['Nuttycoco'/134, l='Test world 2', x=67.66, y=4.00, z=-1216.01]]
	Chunk stats: ServerChunkCache: 937 Drop: 0
	Level seed: -2057614685529082366
	Level generator: ID 01 - flat, ver 0. Features enabled: true
	Level generator options: 
	Level spawn location: World: (105,4,-704), Chunk: (at 9,0,0 in 6,-44; contains blocks 96,0,-704 to 111,255,-689), Region: (0,-2; contains chunks 0,-64 to 31,-33, blocks 0,0,-1024 to 511,255,-513)
	Level time: 1222791 game time, 18793 day time
	Level dimension: 0
	Level storage version: 0x04ABD - Anvil
	Level weather: Rain time: 40313 (now: false), thunder time: 35627 (now: false)
	Level game mode: Game mode: creative (ID 1). Hardcore: false. Cheats: true
Stacktrace:
	at net.minecraft.server.MinecraftServer.u(SourceFile:502)
	at net.minecraft.server.MinecraftServer.t(SourceFile:440)
	at btk.t(SourceFile:117)
	at net.minecraft.server.MinecraftServer.run(SourceFile:357)
	at lb.run(SourceFile:616)

-- System Details --
Details:
	Minecraft Version: 1.7.4
	Operating System: Windows 7 (x86) version 6.1
	Java Version: 1.7.0_51, Oracle Corporation
	Java VM Version: Java HotSpot(TM) Client VM (mixed mode, sharing), Oracle Corporation
	Memory: 60219848 bytes (57 MB) / 156672000 bytes (149 MB) up to 518979584 bytes (494 MB)
	JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx512M
	AABB Pool Size: 1648 (92288 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
	IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
	Profiler Position: N/A (disabled)
	Vec3 Pool Size: 162 (9072 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
	Player Count: 1 / 8; [mp['Nuttycoco'/134, l='Test world 2', x=67.66, y=4.00, z=-1216.01]]
	Type: Integrated Server (map_client.txt)
	Is Modded: Probably not. Jar signature remains and both client + server brands are untouched.