Hopper: java.lang.RuntimeException: Already decorating!!

This is an automatically generated report based from the following crash: http://hopper.minecraft.net/crashes/minecraft/MCX-866/

Crash:

java.lang.RuntimeException: Already decorating!!
	at act.a(SourceFile:21)
	at acp.a(SourceFile:217)
	at aes.a(SourceFile:454)
	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:2241)
	at re.a(SourceFile:78)
	at re.a(SourceFile:82)
	at ql.c(SourceFile:41)
	at ps.a(SourceFile:91)
	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 ----
// I feel sad now :(

Time: 13. 8. 4 오후 12:51
Description: Ticking entity

java.lang.RuntimeException: Already decorating!!
	at act.a(SourceFile:21)
	at acp.a(SourceFile:217)
	at aes.a(SourceFile:454)
	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:2241)
	at re.a(SourceFile:78)
	at re.a(SourceFile:82)
	at ql.c(SourceFile:41)
	at ps.a(SourceFile:91)
	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 act.a(SourceFile:21)
	at acp.a(SourceFile:217)
	at aes.a(SourceFile:454)
	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:2241)
	at re.a(SourceFile:78)
	at re.a(SourceFile:82)
	at ql.c(SourceFile:41)
	at ps.a(SourceFile:91)
	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: 605
	Entity Name: 좀비
	Entity's Exact location: 293.50, 31.00, -15.50
	Entity's Block location: World: (293,31,-16), Chunk: (at 5,1,0 in 18,-1; contains blocks 288,0,-16 to 303,255,-1), Region: (0,-1; contains chunks 0,-32 to 31,-1, blocks 0,0,-512 to 511,255,-1)
	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: Demo_World
	All players: 0 total; []
	Chunk stats: ServerChunkCache: 465 Drop: 0
	Level seed: -343522682
	Level generator: ID 00 - default, ver 1. Features enabled: true
	Level generator options: 
	Level spawn location: World: (216,64,-92), Chunk: (at 8,4,4 in 13,-6; contains blocks 208,0,-96 to 223,255,-81), Region: (0,-1; contains chunks 0,-32 to 31,-1, blocks 0,0,-512 to 511,255,-1)
	Level time: 36 game time, 36 day time
	Level dimension: 0
	Level storage version: 0x04ABD - Anvil
	Level weather: Rain time: 128409 (now: false), thunder time: 31294 (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 XP (x86) version 5.1
	Java Version: 1.7.0_25, Oracle Corporation
	Java VM Version: Java HotSpot(TM) Client VM (mixed mode, sharing), Oracle Corporation
	Memory: 202046664 bytes (192 MB) / 478662656 bytes (456 MB) up to 518979584 bytes (494 MB)
	JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx512M
	AABB Pool Size: 4414 (247184 bytes; 0 MB) allocated, 2277 (127512 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: 11458 (641648 bytes; 0 MB) allocated, 8926 (499856 bytes; 0 MB) used
	Player Count: 0 / 8; []
	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-866/399422/