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

This is an automatically generated report based from the following crash: http://hopper.minecraft.net/crashes/minecraft/MCX-74300/

Crash:

java.lang.RuntimeException: Already decorating!!
	at adu.a(SourceFile:20)
	at ado.a(SourceFile:350)
	at agb.a(SourceFile:433)
	at kc.a(SourceFile:156)
	at aey.a(SourceFile:771)
	at kc.c(SourceFile:93)
	at kc.d(SourceFile:104)
	at act.e(SourceFile:297)
	at adf.a(SourceFile:21)
	at adf.a(SourceFile:77)
	at kd.b(SourceFile:108)

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

---- Minecraft Crash Report ----
// Everything's going to plan. No, really, that was supposed to happen.

Time: 05/09/13 21:26
Description: Exception ticking world

java.lang.RuntimeException: Already decorating!!
	at adu.a(SourceFile:20)
	at ado.a(SourceFile:350)
	at agb.a(SourceFile:433)
	at kc.a(SourceFile:156)
	at aey.a(SourceFile:771)
	at kc.c(SourceFile:93)
	at kc.d(SourceFile:104)
	at act.e(SourceFile:297)
	at adf.a(SourceFile:21)
	at adf.a(SourceFile:77)
	at kd.b(SourceFile:108)
	at net.minecraft.server.MinecraftServer.t(SourceFile:455)
	at net.minecraft.server.MinecraftServer.s(SourceFile:398)
	at bng.s(SourceFile:124)
	at net.minecraft.server.MinecraftServer.run(SourceFile:332)
	at hs.run(SourceFile:575)


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

-- Head --
Stacktrace:
	at adu.a(SourceFile:20)
	at ado.a(SourceFile:350)
	at agb.a(SourceFile:433)
	at kc.a(SourceFile:156)
	at aey.a(SourceFile:771)
	at kc.c(SourceFile:93)
	at kc.d(SourceFile:104)
	at act.e(SourceFile:297)
	at adf.a(SourceFile:21)
	at adf.a(SourceFile:77)
	at kd.b(SourceFile:108)

-- Affected level --
Details:
	Level name: vallée
	All players: 2 total; [kg['bof_train'/93, l='vallée', x=-899,76, y=64,00, z=-302,77], kg['hordes5'/571, l='vallée', x=29999990,50, y=70,50, z=29999990,50]]
	Chunk stats: ServerChunkCache: 1118 Drop: 0
	Level seed: 5737904576158615207
	Level generator: ID 02 - largeBiomes, ver 0. Features enabled: true
	Level generator options: 
	Level spawn location: World: (-460,64,-409), Chunk: (at 4,4,7 in -29,-26; contains blocks -464,0,-416 to -449,255,-401), Region: (-1,-1; contains chunks -32,-32 to -1,-1, blocks -512,0,-512 to -1,255,-1)
	Level time: 136936 game time, 148883 day time
	Level dimension: 0
	Level storage version: 0x04ABD - Anvil
	Level weather: Rain time: 74830 (now: false), thunder time: 91089 (now: false)
	Level game mode: Game mode: survival (ID 0). Hardcore: false. Cheats: true
Stacktrace:
	at net.minecraft.server.MinecraftServer.t(SourceFile:455)
	at net.minecraft.server.MinecraftServer.s(SourceFile:398)
	at bng.s(SourceFile:124)
	at net.minecraft.server.MinecraftServer.run(SourceFile:332)
	at hs.run(SourceFile:575)

-- System Details --
Details:
	Minecraft Version: 13w36a
	Operating System: Linux (amd64) version 3.2.0-52-generic
	Java Version: 1.7.0_25, Oracle Corporation
	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
	Memory: 135916216 bytes (129 MB) / 301006848 bytes (287 MB) up to 954466304 bytes (910 MB)
	JVM Flags: 1 total; -Xmx1G
	AABB Pool Size: 5342 (299152 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
	Suspicious classes: [com.ibm.icu.text.ArabicShapingException], [gnu.trove.TIntCollection], [gnu.trove.impl.HashFunctions, PrimeFinder], [gnu.trove.impl.hash.THash, TPrimitiveHash, TIntIntHash], [gnu.trove.iterator.TIterator, TAdvancingIterator, TIntIntIterator], [gnu.trove.map.TIntIntMap], [gnu.trove.map.hash.TIntIntHashMap], [gnu.trove.procedure.TIntIntProcedure], [gnu.trove.set.TIntSet]
	IntCache: cache: 0, tcache: 0, allocated: 13, tallocated: 103
	Profiler Position: N/A (disabled)
	Vec3 Pool Size: 1225 (68600 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
	Player Count: 2 / 8; [kg['bof_train'/93, l='vallée', x=-899,76, y=64,00, z=-302,77], kg['hordes5'/571, l='vallée', x=29999990,50, y=70,50, z=29999990,50]]
	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-74300/8240770/