System crashes within seconds of loading

After loading most recent snapshot game crashes within seconds.

---- Minecraft Crash Report ----
// Who set us up the TNT?

Time: 09/07/14 7:08 PM
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: Looking15
All players: 1 total; [qj['JTPinWpg'/160, l='Looking15', x=-9.96, y=14.00, z=-243.54]]
Chunk stats: ServerChunkCache: 863 Drop: 0
Level seed: 69
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":true,"useDungeons":true,"dungeonChance":24,"useStrongholds":true,"useVillages":true,"useMineShafts":true,"useTemples":true,"useMonuments":true,"useRavines":true,"useWaterLakes":true,"waterLakeChance":4,"useLavaLakes":true,"lavaLakeChance":88,"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: 256.00,64.00,-208.00 - World: (256,64,-208), Chunk: (at 0,4,0 in 16,-13; contains blocks 256,0,-208 to 271,255,-193), Region: (0,-1; contains chunks 0,-32 to 31,-1, blocks 0,0,-512 to 511,255,-1)
Level time: 413741 game time, 507308 day time
Level dimension: 0
Level storage version: 0x04ABD - Anvil
Level weather: Rain time: 83792 (now: false), thunder time: 128635 (now: false)
Level game mode: Game mode: survival (ID 0). Hardcore: false. Cheats: false
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)