Hopper: java.lang.NullPointerException: Ticking entity

This is an automatically generated report based from the following crash: http://hopper.minecraft.net/crashes/minecraft/MCX-312517/

Crash:

java.lang.NullPointerException: Ticking entity
	at vn.a(SourceFile:133)
	at vn.k(SourceFile:120)
	at vn.h(SourceFile:95)
	at afe.a(SourceFile:1367)
	at mc.a(SourceFile:479)
	at afe.g(SourceFile:1345)

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

---- Minecraft Crash Report ----
// Don't be sad, have a hug! <3

Time: 11.10.13 17:46
Description: Ticking entity

java.lang.NullPointerException: Ticking entity
	at vn.a(SourceFile:133)
	at vn.k(SourceFile:120)
	at vn.h(SourceFile:95)
	at afe.a(SourceFile:1367)
	at mc.a(SourceFile:479)
	at afe.g(SourceFile:1345)
	at afe.h(SourceFile:1252)
	at mc.h(SourceFile:364)
	at net.minecraft.server.MinecraftServer.u(SourceFile:511)
	at net.minecraft.server.MinecraftServer.t(SourceFile:441)
	at brh.t(SourceFile:117)
	at net.minecraft.server.MinecraftServer.run(SourceFile:358)
	at kt.run(SourceFile:617)


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

-- Head --
Stacktrace:
	at vn.a(SourceFile:133)
	at vn.k(SourceFile:120)
	at vn.h(SourceFile:95)
	at afe.a(SourceFile:1367)
	at mc.a(SourceFile:479)
	at afe.g(SourceFile:1345)

-- Entity being ticked --
Details:
	Entity Type: Item (vn)
	Entity ID: 13451
	Entity Name: ~~ERROR~~ NullPointerException: null
	Entity's Exact location: 185,95, 63,23, -425,36
	Entity's Block location: World: (185,63,-426), Chunk: (at 9,3,6 in 11,-27; contains blocks 176,0,-432 to 191,255,-417), Region: (0,-1; contains chunks 0,-32 to 31,-1, blocks 0,0,-512 to 511,255,-1)
	Entity's Momentum: -0,14, -0,94, -0,04
Stacktrace:
	at afe.h(SourceFile:1252)
	at mc.h(SourceFile:364)

-- Affected level --
Details:
	Level name: yolo
	All players: 1 total; [mf['Karate123lp'/84, l='yolo', x=193,53, y=78,50, z=-423,48]]
	Chunk stats: ServerChunkCache: 671 Drop: 0
	Level seed: 3714841
	Level generator: ID 00 - default, ver 1. Features enabled: true
	Level generator options: 
	Level spawn location: World: (223,64,-311), Chunk: (at 15,4,9 in 13,-20; contains blocks 208,0,-320 to 223,255,-305), Region: (0,-1; contains chunks 0,-32 to 31,-1, blocks 0,0,-512 to 511,255,-1)
	Level time: 195805 game time, 81715 day time
	Level dimension: 0
	Level storage version: 0x04ABD - Anvil
	Level weather: Rain time: 60209 (now: false), thunder time: 96148 (now: false)
	Level game mode: Game mode: survival (ID 0). Hardcore: false. Cheats: true
Stacktrace:
	at net.minecraft.server.MinecraftServer.u(SourceFile:511)
	at net.minecraft.server.MinecraftServer.t(SourceFile:441)
	at brh.t(SourceFile:117)
	at net.minecraft.server.MinecraftServer.run(SourceFile:358)
	at kt.run(SourceFile:617)

-- System Details --
Details:
	Minecraft Version: 13w41b
	Operating System: Windows 7 (x86) version 6.1
	Java Version: 1.7.0_21, Oracle Corporation
	Java VM Version: Java HotSpot(TM) Client VM (mixed mode, sharing), Oracle Corporation
	Memory: 130329232 bytes (124 MB) / 292814848 bytes (279 MB) up to 518979584 bytes (494 MB)
	JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx512M
	AABB Pool Size: 2695 (150920 bytes; 0 MB) allocated, 2502 (140112 bytes; 0 MB) used
	IntCache: cache: 0, tcache: 0, allocated: 12, tallocated: 94
	Profiler Position: N/A (disabled)
	Vec3 Pool Size: 972 (54432 bytes; 0 MB) allocated, 711 (39816 bytes; 0 MB) used
	Player Count: 1 / 8; [mf['Karate123lp'/84, l='yolo', x=193,53, y=78,50, z=-423,48]]
	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-312517/16832965/