Just went to launch screen

Minecraft Crash Report ----
// I just don't know what went wrong 😞

Time: 12/15/14 10:11 AM
Description: Exception ticking world

java.lang.RuntimeException: Already decorating
at arv.a(SourceFile:25)
at arj.a(SourceFile:389)
at asa.a(SourceFile:143)
at bgt.a(SourceFile:472)
at qt.a(SourceFile:174)
at bff.a(SourceFile:845)
at qt.c(SourceFile:104)
at qt.d(SourceFile:116)
at aqr.a(SourceFile:276)
at qu.h(SourceFile:327)
at qu.c(SourceFile:202)
at net.minecraft.server.MinecraftServer.A(SourceFile:600)
at net.minecraft.server.MinecraftServer.z(SourceFile:532)
at cyk.z(SourceFile:155)
at net.minecraft.server.MinecraftServer.run(SourceFile:448)
at java.lang.Thread.run(Unknown Source)

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

– Head –
Stacktrace:
at arv.a(SourceFile:25)
at arj.a(SourceFile:389)
at asa.a(SourceFile:143)
at bgt.a(SourceFile:472)
at qt.a(SourceFile:174)
at bff.a(SourceFile:845)
at qt.c(SourceFile:104)
at qt.d(SourceFile:116)
at aqr.a(SourceFile:276)
at qu.h(SourceFile:327)
at qu.c(SourceFile:202)

– Affected level –
Details:
Level name: 121314
All players: 1 total; [qx['Pokefriend2014'/21522382, l='121314', x=-911.36, y=90.68, z=-1137.40]]
Chunk stats: ServerChunkCache: 895 Drop: 0
Level seed: -880057791687441506
Level generator: ID 04 - customized, ver 0. Features enabled: true
Level generator options: {"coordinateScale":684.412,"heightScale":684.412,"lowerLimitScale":512.0,"upperLimitScale":512.0,"depthNoiseScaleX":200.0,"depthNoiseScaleZ":200.0,"depthNoiseScaleExponent":0.5,"mainNoiseScaleX":80.0,"mainNoiseScaleY":160.0,"mainNoiseScaleZ":80.0,"baseSize":8.5,"stretchY":12.0,"biomeDepthWeight":1.0,"biomeDepthOffset":0.0,"biomeScaleWeight":1.0,"biomeScaleOffset":0.0,"seaLevel":63,"useCaves":false,"useDungeons":false,"dungeonChance":8,"useStrongholds":true,"useVillages":true,"useMineShafts":false,"useTemples":true,"useMonuments":true,"useRavines":false,"useWaterLakes":true,"waterLakeChance":25,"useLavaLakes":true,"lavaLakeChance":80,"useLavaOceans":false,"fixedBiome":-1,"biomeSize":4,"riverSize":4,"dirtSize":33,"dirtCount":10,"dirtMinHeight":0,"dirtMaxHeight":256,"gravelSize":33,"gravelCount":8,"gravelMinHeight":0,"gravelMaxHeight":256,"graniteSize":33,"graniteCount":10,"graniteMinHeight":0,"graniteMaxHeight":80,"dioriteSize":33,"dioriteCount":10,"dioriteMinHeight":0,"dioriteMaxHeight":80,"andesiteSize":33,"andesiteCount":10,"andesiteMinHeight":0,"andesiteMaxHeight":80,"coalSize":17,"coalCount":20,"coalMinHeight":0,"coalMaxHeight":128,"ironSize":9,"ironCount":20,"ironMinHeight":0,"ironMaxHeight":64,"goldSize":9,"goldCount":2,"goldMinHeight":0,"goldMaxHeight":32,"redstoneSize":8,"redstoneCount":8,"redstoneMinHeight":0,"redstoneMaxHeight":16,"diamondSize":8,"diamondCount":1,"diamondMinHeight":0,"diamondMaxHeight":16,"lapisSize":7,"lapisCount":1,"lapisCenterHeight":16,"lapisSpread":16}
Level spawn location: 84.00,64.00,256.00 - World: (84,64,256), Chunk: (at 4,4,0 in 5,16; contains blocks 80,0,256 to 95,255,271), Region: (0,0; contains chunks 0,0 to 31,31, blocks 0,0,0 to 511,255,511)
Level time: 1064348 game time, 1064348 day time
Level dimension: 0
Level storage version: 0x04ABD - Anvil
Level weather: Rain time: 144656 (now: false), thunder time: 61791 (now: false)
Level game mode: Game mode: survival (ID 0). Hardcore: false. Cheats: true
Stacktrace:
at net.minecraft.server.MinecraftServer.A(SourceFile:600)
at net.minecraft.server.MinecraftServer.z(SourceFile:532)
at cyk.z(SourceFile:155)
at net.minecraft.server.MinecraftServer.run(SourceFile:448)
at java.lang.Thread.run(Unknown Source)

– System Details –
Details:
Minecraft Version: 1.8.1
Operating System: Windows XP (x86) version 5.1
Java Version: 1.7.0_71, Oracle Corporation
Java VM Version: Java HotSpot(TM) Client VM (mixed mode), Oracle Corporation
Memory: 181532624 bytes (173 MB) / 523501568 bytes (499 MB) up to 523501568 bytes (499 MB)
JVM Flags: 6 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx512M -XX:+UseConcMarkSweepGC -XX:+CMSIncrementalMode -XX:-UseAdaptiveSizePolicy -Xmn128M
IntCache: cache: 0, tcache: 0, allocated: 13, tallocated: 95
Profiler Position: N/A (disabled)
Player Count: 1 / 8; [qx['Pokefriend2014'/21522382, l='121314', x=-911.36, y=90.68, z=-1137.40]]
Type: Integrated Server (map_client.txt)
Is Modded: Probably not. Jar signature remains and both client + server brands are untouched.