Hopper: java.lang.NullPointerException: Ticking entity

This is an automatically generated report based from the following crash: http://hopper.minecraft.net/crashes/minecraft/MCX-1194815/

Crash:

java.lang.NullPointerException: Ticking entity
	at ait.E(SourceFile:189)
	at ait.c(SourceFile:195)
	at sz.e(SourceFile:112)
	at sx.l_(SourceFile:91)
	at ait.a(SourceFile:1367)
	at nu.a(SourceFile:528)
	at ait.g(SourceFile:1345)

The following is the first clean report made public about this crash:

---- Minecraft Crash Report ----
// Sorry :(

Time: 2/6/14 1:32 PM
Description: Ticking entity

java.lang.NullPointerException: Ticking entity
	at ait.E(SourceFile:189)
	at ait.c(SourceFile:195)
	at sz.e(SourceFile:112)
	at sx.l_(SourceFile:91)
	at ait.a(SourceFile:1367)
	at nu.a(SourceFile:528)
	at ait.g(SourceFile:1345)
	at ait.i(SourceFile:1250)
	at nu.i(SourceFile:401)
	at net.minecraft.server.MinecraftServer.v(SourceFile:527)
	at net.minecraft.server.MinecraftServer.u(SourceFile:461)
	at cbr.u(SourceFile:125)
	at net.minecraft.server.MinecraftServer.run(SourceFile:377)
	at mk.run(SourceFile:647)


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

-- Head --
Stacktrace:
	at ait.E(SourceFile:189)
	at ait.c(SourceFile:195)
	at sz.e(SourceFile:112)
	at sx.l_(SourceFile:91)
	at ait.a(SourceFile:1367)
	at nu.a(SourceFile:528)
	at ait.g(SourceFile:1345)

-- Entity being ticked --
Details:
	Entity Type: LeashKnot (sz)
	Entity ID: 31850
	Entity Name: entity.LeashKnot.name
	Entity's Exact location: -532.50, 76.00, 128.50
	Entity's Block location: -533.00,76.00,128.00 - World: (-533,76,128), Chunk: (at 11,4,0 in -34,8; contains blocks -544,0,128 to -529,255,143), 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
	Entity's Rider: ~~ERROR~~ NullPointerException: null
	Entity's Vehicle: ~~ERROR~~ NullPointerException: null
Stacktrace:
	at ait.i(SourceFile:1250)
	at nu.i(SourceFile:401)

-- Affected level --
Details:
	Level name: NIGGA NUTELLA
	All players: 1 total; [nx['SuperNeffyBoy'/499, l='NIGGA NUTELLA', x=-532.56, y=76.49, z=128.00]]
	Chunk stats: ServerChunkCache: 604 Drop: 0
	Level seed: 577774299
	Level generator: ID 00 - default, ver 1. Features enabled: true
	Level generator options: 
	Level spawn location: -220.00,64.00,168.00 - World: (-220,64,168), Chunk: (at 4,4,8 in -14,10; contains blocks -224,0,160 to -209,255,175), Region: (-1,0; contains chunks -32,0 to -1,31, blocks -512,0,0 to -1,255,511)
	Level time: 35800 game time, 35800 day time
	Level dimension: 0
	Level storage version: 0x04ABD - Anvil
	Level weather: Rain time: 52961 (now: false), thunder time: 95863 (now: false)
	Level game mode: Game mode: creative (ID 1). Hardcore: false. Cheats: true
Stacktrace:
	at net.minecraft.server.MinecraftServer.v(SourceFile:527)
	at net.minecraft.server.MinecraftServer.u(SourceFile:461)
	at cbr.u(SourceFile:125)
	at net.minecraft.server.MinecraftServer.run(SourceFile:377)
	at mk.run(SourceFile:647)

-- System Details --
Details:
	Minecraft Version: 14w06b
	Operating System: Windows 8 (x86) version 6.2
	Java Version: 1.7.0_51, Oracle Corporation
	Java VM Version: Java HotSpot(TM) Client VM (mixed mode, sharing), Oracle Corporation
	Memory: 104440032 bytes (99 MB) / 269631488 bytes (257 MB) up to 518979584 bytes (494 MB)
	JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx512M
	IntCache: cache: 1, tcache: 1, allocated: 12, tallocated: 94
	Profiler Position: N/A (disabled)
	Player Count: 1 / 8; [nx['SuperNeffyBoy'/499, l='NIGGA NUTELLA', x=-532.56, y=76.49, z=128.00]]
	Type: Integrated Server (map_client.txt)
	Is Modded: Probably not. Jar signature remains and both client + server brands are untouched.

You can see this full report at http://hopper.minecraft.net/crashes/minecraft/MCX-1194815/57533293/