Hopper: java.lang.ClassCastException: xd cannot be cast to bay

java.lang.ClassCastException: xd cannot be cast to bay
	at baw.a(SourceFile:176)
	at bai.b(SourceFile:424)
	at baw.b(SourceFile:412)
	at azi.d(SourceFile:241)
	at baw.d(SourceFile:489)
	at azi.m(SourceFile:208)

---- Minecraft Crash Report ----
// Would you like a cupcake?

Time: 9/13/13 2:33 PM
Description: Updating screen events

java.lang.ClassCastException: xd cannot be cast to bay
	at baw.a(SourceFile:176)
	at bai.b(SourceFile:424)
	at baw.b(SourceFile:412)
	at azi.d(SourceFile:241)
	at baw.d(SourceFile:489)
	at azi.m(SourceFile:208)
	at awo.m(SourceFile:1210)
	at awo.V(SourceFile:690)
	at awo.e(SourceFile:646)
	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:
---------------------------------------------------------------------------------------

-- Head --
Stacktrace:
	at baw.a(SourceFile:176)
	at bai.b(SourceFile:424)
	at baw.b(SourceFile:412)
	at azi.d(SourceFile:241)
	at baw.d(SourceFile:489)
	at azi.m(SourceFile:208)

-- Affected screen --
Details:
	Screen name: baw

-- Affected level --
Details:
	Level name: MpServer
	All players: 1 total; [bfz['Minecraft 001'/232, l='MpServer', x=-5.70, y=61.62, z=4.18]]
	Chunk stats: MultiplayerChunkCache: 271, 271
	Level seed: 0
	Level generator: ID 00 - default, ver 1. Features enabled: false
	Level generator options: 
	Level spawn location: World: (8,64,8), Chunk: (at 8,4,8 in 0,0; contains blocks 0,0,0 to 15,255,15), Region: (0,0; contains chunks 0,0 to 31,31, blocks 0,0,0 to 511,255,511)
	Level time: 823324 game time, 925693 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: survival (ID 0). Hardcore: false. Cheats: false
	Forced entities: 82 total; [ur['Esqueleto'/95181, l='MpServer', x=31.50, y=30.00, z=-1.50], sm['Murciélago'/96133, l='MpServer', x=26.72, y=35.60, z=-23.25], sm['Murciélago'/96132, l='MpServer', x=23.25, y=33.02, z=-27.56], sm['Murciélago'/96135, l='MpServer', x=29.13, y=34.00, z=-25.72], sm['Murciélago'/96136, l='MpServer', x=22.09, y=33.05, z=-28.28], ur['Esqueleto'/91535, l='MpServer', x=-25.50, y=34.00, z=78.50], uw['Zombi'/97233, l='MpServer', x=-4.65, y=49.00, z=52.80], sm['Murciélago'/94810, l='MpServer', x=-2.72, y=19.10, z=11.72], ur['Esqueleto'/94142, l='MpServer', x=-69.16, y=50.00, z=82.50], ur['Esqueleto'/96855, l='MpServer', x=-80.50, y=30.00, z=-20.50], sm['Murciélago'/93572, l='MpServer', x=-55.59, y=37.29, z=40.75], ut['Araña'/97230, l='MpServer', x=63.28, y=64.00, z=-14.28], ur['Esqueleto'/91536, l='MpServer', x=-25.50, y=34.00, z=82.50], uf['Creeper'/78531, l='MpServer', x=4.56, y=39.00, z=9.97], uw['Zombi'/97222, l='MpServer', x=62.50, y=64.00, z=-11.50], uf['Creeper'/97219, l='MpServer', x=-32.50, y=25.00, z=70.50], us['Slime'/57429, l='MpServer', x=-0.69, y=14.00, z=24.31], ur['Esqueleto'/96856, l='MpServer', x=-79.50, y=30.00, z=-16.50], ta['Calamar'/95376, l='MpServer', x=-43.97, y=59.19, z=18.50], ur['Esqueleto'/95792, l='MpServer', x=17.50, y=29.00, z=45.50], sq['Salvaje'/57447, l='MpServer', x=23.59, y=64.00, z=8.63], uf['Creeper'/73037, l='MpServer', x=13.53, y=45.00, z=19.03], uw['Zombi'/96181, l='MpServer', x=-21.19, y=73.00, z=-7.98], uw['Zombi'/95791, l='MpServer', x=-52.50, y=15.00, z=-58.50], pb['entity.ItemFrame.name'/57470, l='MpServer', x=28.06, y=66.50, z=-5.50], ta['Calamar'/95375, l='MpServer', x=-49.16, y=60.03, z=24.59], ta['Calamar'/95374, l='MpServer', x=-41.06, y=60.00, z=23.06], ta['Calamar'/95373, l='MpServer', x=-45.59, y=60.31, z=26.31], uw['Zombi'/96185, l='MpServer', x=-47.88, y=22.00, z=-39.50], ta['Calamar'/95372, l='MpServer', x=-51.94, y=55.78, z=-25.22], ta['Calamar'/95371, l='MpServer', x=-48.22, y=56.19, z=-20.75], ta['Calamar'/95370, l='MpServer', x=-47.16, y=57.69, z=-26.09], ta['Calamar'/95369, l='MpServer', x=-44.59, y=57.28, z=-27.28], uw['Zombi'/96890, l='MpServer', x=57.50, y=67.00, z=-64.50], sm['Murciélago'/92436, l='MpServer', x=-55.50, y=16.73, z=-36.41], ur['Esqueleto'/87461, l='MpServer', x=-70.50, y=16.00, z=-1.50], td['Lobo'/57479, l='MpServer', x=30.19, y=64.00, z=5.38], ur['Esqueleto'/88918, l='MpServer', x=38.50, y=27.00, z=45.50], td['General'/57478, l='MpServer', x=29.94, y=64.00, z=3.56], td['Lobo'/57477, l='MpServer', x=24.88, y=64.00, z=10.03], td['Lobo'/57476, l='MpServer', x=24.38, y=64.00, z=4.44], uw['Zombi'/89130, l='MpServer', x=10.47, y=38.00, z=63.06], td['Lobo'/57475, l='MpServer', x=22.75, y=64.00, z=2.31], pb['entity.ItemFrame.name'/57474, l='MpServer', x=21.06, y=62.50, z=6.50], uf['Creeper'/96205, l='MpServer', x=-47.50, y=30.00, z=73.50], uw['Zombi'/92987, l='MpServer', x=-72.50, y=34.00, z=82.50], uw['Zombi'/95824, l='MpServer', x=-82.50, y=29.00, z=57.50], td['Lobo'/57480, l='MpServer', x=30.84, y=64.00, z=7.91], uw['Zombi'/95822, l='MpServer', x=-76.50, y=30.00, z=55.97], uw['Zombi'/95823, l='MpServer', x=-81.50, y=29.00, z=57.50], ur['Esqueleto'/96222, l='MpServer', x=23.50, y=63.00, z=-32.50], sm['Murciélago'/92431, l='MpServer', x=14.25, y=19.10, z=19.53], uw['Zombi'/96223, l='MpServer', x=-47.50, y=27.00, z=48.50], sm['Murciélago'/92430, l='MpServer', x=6.78, y=16.89, z=22.69], uf['Creeper'/92334, l='MpServer', x=-8.50, y=47.00, z=64.50], uf['Creeper'/85910, l='MpServer', x=58.50, y=15.00, z=-33.50], uw['Zombi'/96225, l='MpServer', x=-45.50, y=27.00, z=46.50], uw['Zombi'/96224, l='MpServer', x=-48.50, y=27.00, z=47.50], ur['Esqueleto'/97202, l='MpServer', x=-54.90, y=30.00, z=-38.50], bfz['Minecraft 001'/232, l='MpServer', x=-5.70, y=61.62, z=4.18], ur['Esqueleto'/97200, l='MpServer', x=70.50, y=65.00, z=68.50], uf['Creeper'/93418, l='MpServer', x=-19.50, y=43.00, z=64.50], ur['Esqueleto'/86226, l='MpServer', x=-71.50, y=21.00, z=72.50], ur['Esqueleto'/97201, l='MpServer', x=-59.50, y=30.00, z=-36.50], uf['Creeper'/97206, l='MpServer', x=3.50, y=22.00, z=64.50], sx['Oveja'/57377, l='MpServer', x=-70.94, y=63.00, z=-52.88], sm['Murciélago'/95452, l='MpServer', x=75.45, y=29.70, z=-27.25], uw['Zombi'/95317, l='MpServer', x=-33.34, y=15.00, z=65.66], sm['Murciélago'/95453, l='MpServer', x=-74.52, y=18.75, z=17.41], sw['Cerdo'/57525, l='MpServer', x=65.50, y=73.00, z=-45.31], uf['Creeper'/91725, l='MpServer', x=-76.56, y=35.00, z=73.97], uf['Creeper'/89232, l='MpServer', x=-40.50, y=30.00, z=76.50], sm['Murciélago'/96122, l='MpServer', x=52.50, y=16.07, z=79.88], uf['Creeper'/94892, l='MpServer', x=-57.50, y=23.00, z=83.50], ur['Esqueleto'/92695, l='MpServer', x=-34.69, y=16.00, z=13.44], sm['Murciélago'/96121, l='MpServer', x=45.47, y=16.00, z=79.63], ur['Esqueleto'/90147, l='MpServer', x=-20.44, y=46.00, z=80.06], uw['Zombi'/95569, l='MpServer', x=-44.50, y=37.00, z=0.50], uw['Zombi'/95568, l='MpServer', x=-43.50, y=37.00, z=-0.50], ur['Esqueleto'/95571, l='MpServer', x=-46.50, y=37.00, z=0.50], uw['Zombi'/95570, l='MpServer', x=-44.50, y=37.00, z=-1.50], uf['Creeper'/89482, l='MpServer', x=37.50, y=29.00, z=-2.50]]
	Retry entities: 0 total; []
	Server brand: vanilla
	Server type: Integrated singleplayer server
Stacktrace:
	at bfu.a(SourceFile:285)
	at awo.b(SourceFile:1821)
	at awo.e(SourceFile:655)
	at net.minecraft.client.main.Main.main(SourceFile:103)

-- System Details --
Details:
	Minecraft Version: 13w37b
	Operating System: Windows 7 (x86) version 6.1
	Java Version: 1.7.0_25, Oracle Corporation
	Java VM Version: Java HotSpot(TM) Client VM (mixed mode), Oracle Corporation
	Memory: 104602256 bytes (99 MB) / 356024320 bytes (339 MB) up to 1037959168 bytes (989 MB)
	JVM Flags: 1 total; -Xmx1G
	AABB Pool Size: 3556 (199136 bytes; 0 MB) allocated, 2 (112 bytes; 0 MB) used
	IntCache: cache: 0, tcache: 0, allocated: 13, tallocated: 95
	Launched Version: 13w37b
	LWJGL: 2.9.0
	OpenGL: Intel(R) HD Graphics GL version 2.1.0 - Build 8.15.10.2141, Intel
	Is Modded: Probably not. Jar signature remains and client brand is untouched.
	Type: Client (map_client.txt)
	Resource Packs: []
	Current Language: Español (España)
	Profiler Position: N/A (disabled)
	Vec3 Pool Size: 3383 (189448 bytes; 0 MB) allocated, 17 (952 bytes; 0 MB) used