Hopper: java.lang.ClassCastException: cj cannot be cast to ch

This is an automatically generated report based from the following crash: http://hopper.minecraft.net/crashes/minecraft/MCX-83898/

Crash:

java.lang.ClassCastException: cj cannot be cast to ch
	at cb.l(SourceFile:200)
	at yk.a(SourceFile:85)
	at yl.a(SourceFile:72)
	at yx.a(SourceFile:433)
	at azr.a(SourceFile:188)
	at baf.a(SourceFile:581)
	at azr.a(SourceFile:168)
	at bai.a(SourceFile:30)
	at baf.a(SourceFile:530)
	at bhh.b(SourceFile:720)
	at avx.V(SourceFile:713)
	at avx.e(SourceFile:642)
	at net.minecraft.client.main.Main.main(SourceFile:103)

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

---- Minecraft Crash Report ----
// I'm sorry, Dave.

Time: 9/6/13 9:43 AM
Description: Reading NBT data

java.lang.ClassCastException: cj cannot be cast to ch
	at cb.l(SourceFile:200)
	at yk.a(SourceFile:85)
	at yl.a(SourceFile:72)
	at yx.a(SourceFile:433)
	at azr.a(SourceFile:188)
	at baf.a(SourceFile:581)
	at azr.a(SourceFile:168)
	at bai.a(SourceFile:30)
	at baf.a(SourceFile:530)
	at bhh.b(SourceFile:720)
	at avx.V(SourceFile:713)
	at avx.e(SourceFile:642)
	at net.minecraft.client.main.Main.main(SourceFile:103)


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

-- Corrupt NBT tag --
Details:
	Tag type found: LIST
	Tag type expected: INT[]
	Tag name: Colors
Stacktrace:
	at cb.l(SourceFile:200)
	at yk.a(SourceFile:85)
	at yl.a(SourceFile:72)
	at yx.a(SourceFile:433)
	at azr.a(SourceFile:188)
	at baf.a(SourceFile:581)
	at azr.a(SourceFile:168)
	at bai.a(SourceFile:30)
	at baf.a(SourceFile:530)

-- Screen render details --
Details:
	Screen name: baf
	Mouse location: Scaled: (258, 163). Absolute: (516, 153)
	Screen size: Scaled: (427, 240). Absolute: (854, 480). Scale factor of 2

-- Affected level --
Details:
	Level name: MpServer
	All players: 1 total; [bfg['Nickardson'/693104, l='MpServer', x=697.02, y=5.62, z=-2018.21]]
	Chunk stats: MultiplayerChunkCache: 300, 300
	Level seed: 0
	Level generator: ID 01 - flat, ver 0. Features enabled: false
	Level generator options: 
	Level spawn location: World: (543,4,-2032), Chunk: (at 15,0,0 in 33,-127; contains blocks 528,0,-2032 to 543,255,-2017), Region: (1,-4; contains chunks 32,-128 to 63,-97, blocks 512,0,-2048 to 1023,255,-1537)
	Level time: 200709 game time, 26957 day time
	Level dimension: 0
	Level storage version: 0x00000 - Unknown?
	Level weather: Rain time: 0 (now: false), thunder time: 0 (now: false)
	Level game mode: Game mode: creative (ID 1). Hardcore: false. Cheats: false
	Forced entities: 81 total; [bfg['Nickardson'/693104, l='MpServer', x=697.02, y=5.62, z=-2018.21], tj['item.tile.dirt.default'/639551, l='MpServer', x=649.78, y=3.13, z=-2055.88], tj['item.item.arrow'/697519, l='MpServer', x=638.19, y=4.13, z=-2065.00], tj['item.tile.dirt.default'/639550, l='MpServer', x=648.13, y=3.13, z=-2054.97], tj['item.tile.dirt.default'/655779, l='MpServer', x=634.34, y=3.13, z=-2060.34], tj['item.item.bone'/697520, l='MpServer', x=639.44, y=4.13, z=-2064.16], tw['Creeper'/674720, l='MpServer', x=660.50, y=4.00, z=-2019.50], tj['item.tile.dirt.default'/661807, l='MpServer', x=646.75, y=3.13, z=-2061.06], tw['Creeper'/693140, l='MpServer', x=768.09, y=4.00, z=-1975.22], uk['Spider'/693136, l='MpServer', x=751.50, y=4.00, z=-2022.50], tb['Wither'/47, l='MpServer', x=627.88, y=6.04, z=-2041.75], uj['Slime'/693138, l='MpServer', x=754.65, y=4.00, z=-2012.01], vc['Fireball'/519495, l='MpServer', x=659.47, y=9.00, z=-2057.50], tj['item.tile.dirt.default'/627374, l='MpServer', x=648.59, y=3.13, z=-2059.97], tw['Creeper'/693132, l='MpServer', x=735.50, y=4.00, z=-1950.50], uk['Spider'/693135, l='MpServer', x=744.66, y=4.00, z=-2025.06], tb['Wither'/48, l='MpServer', x=627.66, y=6.04, z=-2040.41], vc['Fireball'/693129, l='MpServer', x=725.47, y=17.00, z=-2045.50], vc['Fireball'/693128, l='MpServer', x=726.47, y=17.00, z=-2048.50], tw['Creeper'/693131, l='MpServer', x=728.47, y=4.00, z=-1952.03], tj['item.tile.dirt.default'/661811, l='MpServer', x=644.88, y=2.13, z=-2060.63], vc['Fireball'/693124, l='MpServer', x=705.47, y=17.00, z=-2045.50], uk['Spider'/693127, l='MpServer', x=722.34, y=4.00, z=-2086.34], tj['item.tile.dirt.default'/661809, l='MpServer', x=643.13, y=3.13, z=-2061.38], uj['Slime'/693126, l='MpServer', x=703.44, y=4.00, z=-2057.65], tb['Wither'/61, l='MpServer', x=623.75, y=6.42, z=-2038.97], vc['Fireball'/693123, l='MpServer', x=705.47, y=14.00, z=-2050.50], vc['Fireball'/693122, l='MpServer', x=716.47, y=14.00, z=-2054.50], tj['item.tile.dirt.default'/661812, l='MpServer', x=644.88, y=2.13, z=-2059.13], tj['item.tile.dirt.default'/656336, l='MpServer', x=636.13, y=3.13, z=-2069.88], tj['item.item.enderPearl'/661154, l='MpServer', x=634.72, y=4.13, z=-2045.91], tj['item.tile.dirt.default'/660212, l='MpServer', x=641.13, y=3.13, z=-2057.88], tj['item.tile.dirt.default'/660213, l='MpServer', x=641.59, y=4.13, z=-2055.72], tj['item.tile.dirt.default'/660216, l='MpServer', x=643.09, y=3.13, z=-2058.28], tj['item.tile.dirt.default'/656330, l='MpServer', x=637.88, y=3.13, z=-2067.25], tj['item.tile.dirt.default'/660218, l='MpServer', x=643.59, y=3.13, z=-2056.16], tj['item.tile.dirt.default'/656332, l='MpServer', x=635.94, y=3.13, z=-2068.53], tj['item.tile.dirt.default'/656333, l='MpServer', x=635.13, y=3.13, z=-2067.13], uj['Slime'/555448, l='MpServer', x=662.31, y=3.08, z=-2049.31], tj['item.tile.dirt.default'/656335, l='MpServer', x=637.13, y=3.13, z=-2068.31], tj['item.item.arrow'/700852, l='MpServer', x=663.16, y=4.13, z=-2073.97], tj['item.item.bone'/700853, l='MpServer', x=663.97, y=4.13, z=-2075.22], sg['Cow'/25006, l='MpServer', x=654.53, y=4.00, z=-2092.31], tj['item.tile.dirt.default'/660182, l='MpServer', x=652.84, y=3.13, z=-2051.00], tj['item.tile.dirt.default'/660180, l='MpServer', x=652.91, y=3.13, z=-2049.66], tj['item.tile.dirt.default'/660184, l='MpServer', x=653.88, y=3.13, z=-2049.13], tj['item.tile.dirt.default'/660185, l='MpServer', x=651.53, y=3.13, z=-2050.88], tj['item.tile.dirt.default'/627463, l='MpServer', x=650.13, y=3.13, z=-2062.81], tj['item.tile.dirt.default'/656975, l='MpServer', x=634.56, y=3.13, z=-2055.84], tj['item.tile.dirt.default'/655898, l='MpServer', x=635.00, y=3.13, z=-2063.72], tj['item.item.rottenFlesh'/700737, l='MpServer', x=723.69, y=4.13, z=-2042.28], tj['item.tile.dirt.default'/655897, l='MpServer', x=635.88, y=3.13, z=-2060.78], so['Sheep'/146, l='MpServer', x=663.19, y=4.00, z=-1956.56], tj['item.item.arrow'/700316, l='MpServer', x=652.13, y=4.13, z=-2039.78], uj['Slime'/700325, l='MpServer', x=758.69, y=4.00, z=-2092.84], uj['Slime'/206212, l='MpServer', x=625.69, y=1.00, z=-2040.35], tj['item.item.arrow'/701006, l='MpServer', x=651.59, y=4.13, z=-2064.28], tj['item.item.bone'/701007, l='MpServer', x=651.59, y=4.13, z=-2064.13], tj['item.tile.dirt.default'/660236, l='MpServer', x=651.84, y=2.13, z=-2062.56], tj['item.tile.dirt.default'/660232, l='MpServer', x=651.31, y=3.13, z=-2063.88], tj['item.tile.dirt.default'/660233, l='MpServer', x=651.69, y=3.13, z=-2061.50], uj['Slime'/700771, l='MpServer', x=695.56, y=4.00, z=-2054.72], tj['item.tile.dirt.default'/660235, l='MpServer', x=652.88, y=2.13, z=-2061.91], tj['item.tile.dirt.default'/664679, l='MpServer', x=646.91, y=3.13, z=-2062.41], vc['Fireball'/693107, l='MpServer', x=675.50, y=14.00, z=-2057.50], tj['item.tile.dirt.default'/664678, l='MpServer', x=645.38, y=3.13, z=-2063.44], vc['Fireball'/693106, l='MpServer', x=685.47, y=9.00, z=-2057.50], tj['item.item.string'/664677, l='MpServer', x=644.78, y=3.13, z=-2062.19], sf['Chicken'/693109, l='MpServer', x=680.50, y=4.00, z=-1954.50], so['Sheep'/693108, l='MpServer', x=679.50, y=4.00, z=-1953.50], tj['item.tile.dirt.default'/664682, l='MpServer', x=645.59, y=3.13, z=-2062.56], tj['item.tile.dirt.default'/664681, l='MpServer', x=643.69, y=3.13, z=-2062.88], tj['item.tile.dirt.default'/656679, l='MpServer', x=635.69, y=2.13, z=-2062.50], tj['item.tile.dirt.default'/656678, l='MpServer', x=634.56, y=2.13, z=-2061.69], tj['item.tile.dirt.default'/656677, l='MpServer', x=634.91, y=2.13, z=-2062.47], tj['item.tile.dirt.default'/656676, l='MpServer', x=636.41, y=3.13, z=-2061.84], so['Sheep'/693102, l='MpServer', x=681.47, y=4.00, z=-1941.22], tj['item.tile.dirt.default'/661744, l='MpServer', x=645.50, y=3.13, z=-2058.78], tw['Creeper'/676072, l='MpServer', x=661.50, y=4.00, z=-2064.50], tj['item.tile.dirt.default'/661743, l='MpServer', x=643.13, y=3.13, z=-2059.81], tj['item.item.string'/661739, l='MpServer', x=648.78, y=3.13, z=-2060.59]]
	Retry entities: 0 total; []
	Server brand: vanilla
	Server type: Non-integrated multiplayer server
Stacktrace:
	at bfb.a(SourceFile:285)
	at avx.b(SourceFile:1813)
	at avx.e(SourceFile:651)
	at net.minecraft.client.main.Main.main(SourceFile:103)

-- System Details --
Details:
	Minecraft Version: 13w36a
	Operating System: Windows 7 (amd64) version 6.1
	Java Version: 1.7.0_25, Oracle Corporation
	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
	Memory: 295341840 bytes (281 MB) / 404226048 bytes (385 MB) up to 954466304 bytes (910 MB)
	JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx1G
	AABB Pool Size: 1079 (60424 bytes; 0 MB) allocated, 2 (112 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: 0, tallocated: 0
	Launched Version: 13w36a
	LWJGL: 2.9.0
	OpenGL: Intel(R) HD Graphics Family GL version 3.1.0 - Build 8.15.10.2361, Intel
	Is Modded: Probably not. Jar signature remains and client brand is untouched.
	Type: Client (map_client.txt)
	Resource Packs: []
	Current Language: English (US)
	Profiler Position: N/A (disabled)
	Vec3 Pool Size: 208 (11648 bytes; 0 MB) allocated, 24 (1344 bytes; 0 MB) used

You can see this full report at http://hopper.minecraft.net/crashes/minecraft/MCX-83898/8328497/