Hopper: java.lang.NullPointerException: Ticking entity

This is an automatically generated report based from the following crash: http://hopper.minecraft.net/crashes/minecraft/MCX-389679/

Crash:

java.lang.NullPointerException: Ticking entity
	at vt.a(SourceFile:133)
	at vt.k(SourceFile:120)
	at vt.h(SourceFile:95)
	at afk.a(SourceFile:1368)
	at mi.a(SourceFile:479)
	at afk.g(SourceFile:1346)

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

---- Minecraft Crash Report ----
// Why did you do that?

Time: 17/10/13 19:54
Description: Ticking entity

java.lang.NullPointerException: Ticking entity
	at vt.a(SourceFile:133)
	at vt.k(SourceFile:120)
	at vt.h(SourceFile:95)
	at afk.a(SourceFile:1368)
	at mi.a(SourceFile:479)
	at afk.g(SourceFile:1346)
	at afk.h(SourceFile:1253)
	at mi.h(SourceFile:364)
	at net.minecraft.server.MinecraftServer.u(SourceFile:511)
	at net.minecraft.server.MinecraftServer.t(SourceFile:441)
	at bsb.t(SourceFile:117)
	at net.minecraft.server.MinecraftServer.run(SourceFile:358)
	at kx.run(SourceFile:617)


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

-- Head --
Stacktrace:
	at vt.a(SourceFile:133)
	at vt.k(SourceFile:120)
	at vt.h(SourceFile:95)
	at afk.a(SourceFile:1368)
	at mi.a(SourceFile:479)
	at afk.g(SourceFile:1346)

-- Entity being ticked --
Details:
	Entity Type: Item (vt)
	Entity ID: 51355
	Entity Name: ~~ERROR~~ NullPointerException: null
	Entity's Exact location: 52.73, 64.13, 434.13
	Entity's Block location: World: (52,64,434), Chunk: (at 4,4,2 in 3,27; contains blocks 48,0,432 to 63,255,447), Region: (0,0; contains chunks 0,0 to 31,31, blocks 0,0,0 to 511,255,511)
	Entity's Momentum: 0.00, 0.00, 0.00
Stacktrace:
	at afk.h(SourceFile:1253)
	at mi.h(SourceFile:364)

-- Affected level --
Details:
	Level name: New World
	All players: 1 total; [ml['iwancole'/191, l='New World', x=52.69, y=65.79, z=435.73]]
	Chunk stats: ServerChunkCache: 624 Drop: 0
	Level seed: 7341775304276263965
	Level generator: ID 00 - default, ver 1. Features enabled: true
	Level generator options: 
	Level spawn location: World: (32,64,256), Chunk: (at 0,4,0 in 2,16; contains blocks 32,0,256 to 47,255,271), Region: (0,0; contains chunks 0,0 to 31,31, blocks 0,0,0 to 511,255,511)
	Level time: 7480 game time, 7480 day time
	Level dimension: 0
	Level storage version: 0x04ABD - Anvil
	Level weather: Rain time: 155193 (now: false), thunder time: 136146 (now: false)
	Level game mode: Game mode: creative (ID 1). Hardcore: false. Cheats: true
Stacktrace:
	at net.minecraft.server.MinecraftServer.u(SourceFile:511)
	at net.minecraft.server.MinecraftServer.t(SourceFile:441)
	at bsb.t(SourceFile:117)
	at net.minecraft.server.MinecraftServer.run(SourceFile:358)
	at kx.run(SourceFile:617)

-- System Details --
Details:
	Minecraft Version: 13w42a
	Operating System: Windows 7 (amd64) version 6.1
	Java Version: 1.7.0_25, Oracle Corporation
	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
	Memory: 382185712 bytes (364 MB) / 890896384 bytes (849 MB) up to 3817799680 bytes (3640 MB)
	JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx4G
	AABB Pool Size: 21983 (1231048 bytes; 1 MB) allocated, 3706 (207536 bytes; 0 MB) used
	IntCache: cache: 1, tcache: 1, allocated: 12, tallocated: 94
	Profiler Position: N/A (disabled)
	Vec3 Pool Size: 1411 (79016 bytes; 0 MB) allocated, 1217 (68152 bytes; 0 MB) used
	Player Count: 1 / 8; [ml['iwancole'/191, l='New World', x=52.69, y=65.79, z=435.73]]
	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-389679/18833931/