Crash

Minecraft Crash Report ----
// Ooh. Shiny.

Time: 10.07.14 14:52
Description: Exception ticking world

java.lang.IllegalArgumentException: Cannot get property bcl{name=age, clazz=class java.lang.Integer, values=[0, 1, 2, 3, 4, 5, 6, 7]} as it does not exist!
at bbw.b(SourceFile:91)
at ayt.b(SourceFile:127)
at ayt.c(SourceFile:69)
at ary.b(SourceFile:416)
at qg.h(SourceFile:373)
at qg.c(SourceFile:199)
at net.minecraft.server.MinecraftServer.x(SourceFile:578)
at net.minecraft.server.MinecraftServer.w(SourceFile:510)
at cwg.w(SourceFile:132)
at net.minecraft.server.MinecraftServer.run(SourceFile:426)
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 bbw.b(SourceFile:91)
at ayt.b(SourceFile:127)
at ayt.c(SourceFile:69)
at ary.b(SourceFile:416)
at qg.h(SourceFile:373)
at qg.c(SourceFile:199)

– Affected level –
Details:
Level name: world
All players: 1 total; [qj['craftdavid'/678, l='world', x=282,98, y=66,00, z=252,39]]
Chunk stats: ServerChunkCache: 1161 Drop: 0
Level seed: -3377072683147438228
Level generator: ID 00 - default, ver 1. Features enabled: true
Level generator options:
Level spawn location: 240,00,64,00,248,00 - World: (240,64,248), Chunk: (at 0,4,8 in 15,15; contains blocks 240,0,240 to 255,255,255), Region: (0,0; contains chunks 0,0 to 31,31, blocks 0,0,0 to 511,255,511)
Level time: 1409227 game time, 195688 day time
Level dimension: 0
Level storage version: 0x04ABD - Anvil
Level weather: Rain time: 94929 (now: false), thunder time: 27835 (now: false)
Level game mode: Game mode: survival (ID 0). Hardcore: false. Cheats: true
Stacktrace:
at net.minecraft.server.MinecraftServer.x(SourceFile:578)
at net.minecraft.server.MinecraftServer.w(SourceFile:510)
at cwg.w(SourceFile:132)
at net.minecraft.server.MinecraftServer.run(SourceFile:426)
at java.lang.Thread.run(Unknown Source)

– System Details –
Details:
Minecraft Version: 14w28a
Operating System: Windows 8 (amd64) version 6.2
Java Version: 1.7.0_51, Oracle Corporation
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
Memory: 284819816 bytes (271 MB) / 757596160 bytes (722 MB) up to 1908932608 bytes (1820 MB)
JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx2G
IntCache: cache: 9, tcache: 0, allocated: 13, tallocated: 95
Profiler Position: N/A (disabled)
Player Count: 1 / 8; [qj['craftdavid'/678, l='world', x=282,98, y=66,00, z=252,39]]
Type: Integrated Server (map_client.txt)
Is Modded: Probably not. Jar signature remains and both client + server brands are untouched.