Hopper: java.lang.ClassCastException: anu cannot be cast to amv

This is an automatically generated report based from the following crash: http://hopper.minecraft.net/crashes/minecraft/MCX-6486/

Crash:

java.lang.ClassCastException: anu cannot be cast to amv
	at amw.<init>(SourceFile:33)
	at amv.a(SourceFile:372)
	at amv.a(SourceFile:334)
	at adq.a(SourceFile:395)
	at abv.f(SourceFile:306)
	at aiq.a(SourceFile:384)
	at aiq.a(SourceFile:513)
	at agh.a(SourceFile:392)
	at ais.a(SourceFile:29)
	at aim.a(SourceFile:72)
	at aes.a(SourceFile:425)
	at jq.a(SourceFile:168)
	at adq.a(SourceFile:732)
	at jq.c(SourceFile:105)
	at jq.d(SourceFile:116)
	at abv.e(SourceFile:289)
	at ack.<init>(SourceFile:32)
	at abv.a(SourceFile:2222)
	at re.a(SourceFile:88)
	at pz.a(SourceFile:38)
	at ps.a(SourceFile:67)
	at of.bh(SourceFile:410)
	at oe.c(SourceFile:1289)
	at of.c(SourceFile:292)
	at tl.c(SourceFile:24)
	at tv.c(SourceFile:141)
	at oe.l_(SourceFile:1176)
	at of.l_(SourceFile:169)
	at tl.l_(SourceFile:29)
	at tv.l_(SourceFile:197)
	at abv.a(SourceFile:1349)
	at jr.a(SourceFile:479)
	at abv.g(SourceFile:1327)

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

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

Time: 9/5/13 4:53 PM
Description: Ticking entity

java.lang.ClassCastException: aqr cannot be cast to amv
	at amw.<init>(SourceFile:33)
	at amv.a(SourceFile:372)
	at amv.a(SourceFile:334)
	at adq.a(SourceFile:395)
	at abv.f(SourceFile:306)
	at aiq.a(SourceFile:384)
	at aiq.a(SourceFile:513)
	at agh.a(SourceFile:392)
	at ais.a(SourceFile:29)
	at aim.a(SourceFile:72)
	at aes.a(SourceFile:425)
	at jq.a(SourceFile:168)
	at adq.a(SourceFile:732)
	at jq.c(SourceFile:105)
	at jq.d(SourceFile:116)
	at abv.e(SourceFile:289)
	at ack.<init>(SourceFile:32)
	at abv.a(SourceFile:2222)
	at re.a(SourceFile:88)
	at pz.a(SourceFile:38)
	at ps.a(SourceFile:67)
	at of.bh(SourceFile:410)
	at oe.c(SourceFile:1289)
	at of.c(SourceFile:292)
	at tl.c(SourceFile:24)
	at tv.c(SourceFile:141)
	at oe.l_(SourceFile:1176)
	at of.l_(SourceFile:169)
	at tl.l_(SourceFile:29)
	at tv.l_(SourceFile:197)
	at abv.a(SourceFile:1349)
	at jr.a(SourceFile:479)
	at abv.g(SourceFile:1327)
	at abv.h(SourceFile:1234)
	at jr.h(SourceFile:364)
	at net.minecraft.server.MinecraftServer.t(SourceFile:470)
	at net.minecraft.server.MinecraftServer.s(SourceFile:405)
	at bkw.s(SourceFile:124)
	at net.minecraft.server.MinecraftServer.run(SourceFile:339)
	at hh.run(SourceFile:582)


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

-- Head --
Stacktrace:
	at amw.<init>(SourceFile:33)
	at amv.a(SourceFile:372)
	at amv.a(SourceFile:334)
	at adq.a(SourceFile:395)
	at abv.f(SourceFile:306)
	at aiq.a(SourceFile:384)
	at aiq.a(SourceFile:513)
	at agh.a(SourceFile:392)
	at ais.a(SourceFile:29)
	at aim.a(SourceFile:72)
	at aes.a(SourceFile:425)
	at jq.a(SourceFile:168)
	at adq.a(SourceFile:732)
	at jq.c(SourceFile:105)
	at jq.d(SourceFile:116)
	at abv.e(SourceFile:289)
	at ack.<init>(SourceFile:32)
	at abv.a(SourceFile:2222)
	at re.a(SourceFile:88)
	at pz.a(SourceFile:38)
	at ps.a(SourceFile:67)
	at of.bh(SourceFile:410)
	at oe.c(SourceFile:1289)
	at of.c(SourceFile:292)
	at tl.c(SourceFile:24)
	at tv.c(SourceFile:141)
	at oe.l_(SourceFile:1176)
	at of.l_(SourceFile:169)
	at tl.l_(SourceFile:29)
	at tv.l_(SourceFile:197)
	at abv.a(SourceFile:1349)
	at jr.a(SourceFile:479)
	at abv.g(SourceFile:1327)

-- Entity being ticked --
Details:
	Entity Type: Zombie (tv)
	Entity ID: 205
	Entity Name: Zombie
	Entity's Exact location: 354.55, 63.00, 236.04
	Entity's Block location: World: (354,63,236), Chunk: (at 2,3,12 in 22,14; contains blocks 352,0,224 to 367,255,239), Region: (0,0; contains chunks 0,0 to 31,31, blocks 0,0,0 to 511,255,511)
	Entity's Momentum: 0.00, -0.08, 0.00
Stacktrace:
	at abv.h(SourceFile:1234)
	at jr.h(SourceFile:364)

-- Affected level --
Details:
	Level name: Survival of the Jasonest
	All players: 1 total; [ju['Minejason16'/190, l='Survival of the Jasonest', x=277.70, y=58.00, z=208.14]]
	Chunk stats: ServerChunkCache: 817 Drop: 0
	Level seed: 5790679943697594492
	Level generator: ID 00 - default, ver 1. Features enabled: true
	Level generator options: 
	Level spawn location: World: (146,64,293), Chunk: (at 2,4,5 in 9,18; contains blocks 144,0,288 to 159,255,303), Region: (0,0; contains chunks 0,0 to 31,31, blocks 0,0,0 to 511,255,511)
	Level time: 253107 game time, 283880 day time
	Level dimension: 0
	Level storage version: 0x04ABD - Anvil
	Level weather: Rain time: 44640 (now: false), thunder time: 49105 (now: false)
	Level game mode: Game mode: survival (ID 0). Hardcore: false. Cheats: false
Stacktrace:
	at net.minecraft.server.MinecraftServer.t(SourceFile:470)
	at net.minecraft.server.MinecraftServer.s(SourceFile:405)
	at bkw.s(SourceFile:124)
	at net.minecraft.server.MinecraftServer.run(SourceFile:339)
	at hh.run(SourceFile:582)

-- System Details --
Details:
	Minecraft Version: 1.6.2
	Operating System: Windows 7 (amd64) version 6.1
	Java Version: 1.7.0_21, Oracle Corporation
	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
	Memory: 178661192 bytes (170 MB) / 337969152 bytes (322 MB) up to 954466304 bytes (910 MB)
	JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx1G
	AABB Pool Size: 3756 (210336 bytes; 0 MB) allocated, 2575 (144200 bytes; 0 MB) used
	Suspicious classes: No suspicious classes found.
	IntCache: cache: 0, tcache: 0, allocated: 3, tallocated: 63
	Profiler Position: N/A (disabled)
	Vec3 Pool Size: 2904 (162624 bytes; 0 MB) allocated, 2361 (132216 bytes; 0 MB) used
	Player Count: 1 / 8; [ju['Minejason16'/190, l='Survival of the Jasonest', x=277.70, y=58.00, z=208.14]]
	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-6486/8179491/