Hopper: java.lang.NullPointerException

java.lang.NullPointerException
	at ny.a(SourceFile:89)
	at ou.aL(SourceFile:396)
	at ou.z(SourceFile:222)
	at ov.z(SourceFile:128)
	at oc.o_(SourceFile:279)
	at ou.o_(SourceFile:1167)
	at ov.o_(SourceFile:169)
	at ud.o_(SourceFile:29)
	at act.a(SourceFile:1365)
	at kd.a(SourceFile:479)
	at act.g(SourceFile:1343)

---- Minecraft Crash Report ----
// This doesn't make any sense!

Time: 9/6/13 7:52 PM
Description: Ticking entity

java.lang.NullPointerException
	at ny.a(SourceFile:89)
	at ou.aL(SourceFile:396)
	at ou.z(SourceFile:222)
	at ov.z(SourceFile:128)
	at oc.o_(SourceFile:279)
	at ou.o_(SourceFile:1167)
	at ov.o_(SourceFile:169)
	at ud.o_(SourceFile:29)
	at act.a(SourceFile:1365)
	at kd.a(SourceFile:479)
	at act.g(SourceFile:1343)
	at act.h(SourceFile:1250)
	at kd.h(SourceFile:364)
	at net.minecraft.server.MinecraftServer.t(SourceFile:463)
	at net.minecraft.server.MinecraftServer.s(SourceFile:398)
	at bnn.s(SourceFile:124)
	at net.minecraft.server.MinecraftServer.run(SourceFile:332)
	at hr.run(SourceFile:575)


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

-- Head --
Stacktrace:
	at ny.a(SourceFile:89)
	at ou.aL(SourceFile:396)
	at ou.z(SourceFile:222)
	at ov.z(SourceFile:128)
	at oc.o_(SourceFile:279)
	at ou.o_(SourceFile:1167)
	at ov.o_(SourceFile:169)
	at ud.o_(SourceFile:29)
	at act.a(SourceFile:1365)
	at kd.a(SourceFile:479)
	at act.g(SourceFile:1343)

-- Entity being ticked --
Details:
	Entity Type: Blaze (tu)
	Entity ID: 5512541
	Entity Name: Blaze
	Entity's Exact location: -685.50, 1.00, 196.50
	Entity's Block location: World: (-686,1,196), Chunk: (at 2,0,4 in -43,12; contains blocks -688,0,192 to -673,255,207), Region: (-2,0; contains chunks -64,0 to -33,31, blocks -1024,0,0 to -513,255,511)
	Entity's Momentum: 0.00, 0.00, 0.00
Stacktrace:
	at act.h(SourceFile:1250)
	at kd.h(SourceFile:364)

-- Affected level --
Details:
	Level name: New World
	All players: 1 total; [kg['MrBloomer'/65, l='New World', x=-685.50, y=1.00, z=191.92]]
	Chunk stats: ServerChunkCache: 663 Drop: 0
	Level seed: 8675309
	Level generator: ID 01 - flat, ver 0. Features enabled: true
	Level generator options: 
	Level spawn location: World: (-690,4,335), Chunk: (at 14,0,15 in -44,20; contains blocks -704,0,320 to -689,255,335), Region: (-2,0; contains chunks -64,0 to -33,31, blocks -1024,0,0 to -513,255,511)
	Level time: 1689383 game time, 15110 day time
	Level dimension: 0
	Level storage version: 0x04ABD - Anvil
	Level weather: Rain time: 5054 (now: false), thunder time: 5054 (now: false)
	Level game mode: Game mode: creative (ID 1). Hardcore: false. Cheats: true
Stacktrace:
	at net.minecraft.server.MinecraftServer.t(SourceFile:463)
	at net.minecraft.server.MinecraftServer.s(SourceFile:398)
	at bnn.s(SourceFile:124)
	at net.minecraft.server.MinecraftServer.run(SourceFile:332)
	at hr.run(SourceFile:575)

-- System Details --
Details:
	Minecraft Version: 13w36b
	Operating System: Windows 7 (amd64) version 6.1
	Java Version: 1.7.0_01, Oracle Corporation
	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
	Memory: 28049968 bytes (26 MB) / 131334144 bytes (125 MB) up to 954466304 bytes (910 MB)
	JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx1G
	AABB Pool Size: 3771 (211176 bytes; 0 MB) allocated, 3266 (182896 bytes; 0 MB) used
	IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
	Profiler Position: N/A (disabled)
	Vec3 Pool Size: 486 (27216 bytes; 0 MB) allocated, 423 (23688 bytes; 0 MB) used
	Player Count: 1 / 8; [kg['MrBloomer'/65, l='New World', x=-685.50, y=1.00, z=191.92]]
	Type: Integrated Server (map_client.txt)
	Is Modded: Probably not. Jar signature remains and both client + server brands are untouched.