Hopper: java.lang.NullPointerException

java.lang.NullPointerException
	at aas.a(SourceFile:54)
	at aba.a(SourceFile:809)
	at wb.a(SourceFile:53)
	at wa.a(SourceFile:81)
	at wu.c(SourceFile:78)
	at vo.a(SourceFile:222)
	at bfa.a(SourceFile:295)
	at azr.a(SourceFile:582)
	at azr.b(SourceFile:555)
	at ayr.d(SourceFile:137)
	at ayr.m(SourceFile:109)

---- Minecraft Crash Report ----
// I bet Cylons wouldn't have this problem.

Time: 6/09/13 0:10
Description: Updating screen events

java.lang.NullPointerException
	at aas.a(SourceFile:54)
	at aba.a(SourceFile:809)
	at wb.a(SourceFile:53)
	at wa.a(SourceFile:81)
	at wu.c(SourceFile:78)
	at vo.a(SourceFile:222)
	at bfa.a(SourceFile:295)
	at azr.a(SourceFile:582)
	at azr.b(SourceFile:555)
	at ayr.d(SourceFile:137)
	at ayr.m(SourceFile:109)
	at avx.m(SourceFile:1202)
	at avx.V(SourceFile:686)
	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:
---------------------------------------------------------------------------------------

-- Head --
Stacktrace:
	at aas.a(SourceFile:54)
	at aba.a(SourceFile:809)
	at wb.a(SourceFile:53)
	at wa.a(SourceFile:81)
	at wu.c(SourceFile:78)
	at vo.a(SourceFile:222)
	at bfa.a(SourceFile:295)
	at azr.a(SourceFile:582)
	at azr.b(SourceFile:555)
	at ayr.d(SourceFile:137)
	at ayr.m(SourceFile:109)

-- Affected screen --
Details:
	Screen name: bad

-- Affected level --
Details:
	Level name: MpServer
	All players: 1 total; [bfg['Nallenito'/6544, l='MpServer', x=207,05, y=67,62, z=-64,06]]
	Chunk stats: MultiplayerChunkCache: 328, 328
	Level seed: 0
	Level generator: ID 00 - default, ver 1. Features enabled: false
	Level generator options: 
	Level spawn location: World: (160,64,-28), Chunk: (at 0,4,4 in 10,-2; contains blocks 160,0,-32 to 175,255,-17), Region: (0,-1; contains chunks 0,-32 to 31,-1, blocks 0,0,-512 to 511,255,-1)
	Level time: 37303 game time, 24415 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: 58 total; [sn['Cerdo'/33048, l='MpServer', x=236,06, y=63,00, z=-46,47], os['entity.ItemFrame.name'/26286, l='MpServer', x=197,50, y=66,50, z=-71,94], sn['Cerdo'/6530, l='MpServer', x=157,81, y=67,00, z=-20,50], sn['Cerdo'/6531, l='MpServer', x=159,19, y=69,00, z=-23,06], sn['Cerdo'/6528, l='MpServer', x=155,34, y=68,00, z=-24,22], sn['Cerdo'/6529, l='MpServer', x=153,50, y=65,00, z=-29,50], os['entity.ItemFrame.name'/355355, l='MpServer', x=206,50, y=69,50, z=-61,94], sd['Murciélago'/884131, l='MpServer', x=280,84, y=26,64, z=-68,66], os['entity.ItemFrame.name'/26360, l='MpServer', x=199,50, y=66,50, z=-71,94], os['entity.ItemFrame.name'/352120, l='MpServer', x=208,50, y=67,50, z=-61,94], os['entity.ItemFrame.name'/26324, l='MpServer', x=198,50, y=66,50, z=-71,94], os['entity.ItemFrame.name'/353290, l='MpServer', x=208,50, y=68,50, z=-61,94], os['entity.ItemFrame.name'/26528, l='MpServer', x=206,50, y=66,50, z=-71,94], sd['Murciélago'/1103054, l='MpServer', x=256,98, y=22,09, z=-127,40], sd['Murciélago'/1103053, l='MpServer', x=255,75, y=21,61, z=-119,25], os['entity.ItemFrame.name'/26504, l='MpServer', x=205,50, y=66,50, z=-71,94], os['entity.ItemFrame.name'/26609, l='MpServer', x=207,50, y=66,50, z=-71,94], os['entity.ItemFrame.name'/26411, l='MpServer', x=201,50, y=66,50, z=-71,94], os['entity.ItemFrame.name'/26391, l='MpServer', x=200,50, y=66,50, z=-71,94], os['entity.ItemFrame.name'/26484, l='MpServer', x=204,50, y=66,50, z=-71,94], os['entity.ItemFrame.name'/26464, l='MpServer', x=203,50, y=66,50, z=-71,94], os['entity.ItemFrame.name'/26447, l='MpServer', x=202,50, y=66,50, z=-71,94], os['entity.ItemFrame.name'/26434, l='MpServer', x=202,50, y=66,50, z=-71,94], bfg['Nallenito'/6544, l='MpServer', x=207,05, y=67,62, z=-64,06], os['entity.ItemFrame.name'/353882, l='MpServer', x=207,50, y=68,50, z=-61,94], sn['Cerdo'/47166, l='MpServer', x=235,06, y=64,00, z=-41,94], so['Oveja'/47167, l='MpServer', x=221,13, y=67,00, z=-46,63], os['entity.ItemFrame.name'/351682, l='MpServer', x=207,50, y=67,50, z=-61,94], sr['Calamar'/882317, l='MpServer', x=229,41, y=56,38, z=-91,75], sr['Calamar'/882315, l='MpServer', x=219,34, y=55,66, z=-93,66], os['entity.ItemFrame.name'/356256, l='MpServer', x=207,50, y=69,50, z=-61,94], sr['Calamar'/882356, l='MpServer', x=169,63, y=47,03, z=-61,50], sr['Calamar'/882355, l='MpServer', x=170,53, y=43,09, z=-74,28], sr['Calamar'/882341, l='MpServer', x=198,01, y=50,20, z=-83,87], sr['Calamar'/882339, l='MpServer', x=215,34, y=48,31, z=-97,91], sd['Murciélago'/1082391, l='MpServer', x=275,94, y=20,95, z=-117,72], os['entity.ItemFrame.name'/351032, l='MpServer', x=206,50, y=67,50, z=-61,94], sg['Vaca'/498275, l='MpServer', x=230,50, y=68,00, z=-44,38], os['entity.ItemFrame.name'/356656, l='MpServer', x=208,50, y=69,50, z=-61,94], sd['Murciélago'/1082535, l='MpServer', x=255,25, y=27,73, z=-112,56], os['entity.ItemFrame.name'/354568, l='MpServer', x=206,50, y=68,50, z=-61,94], sd['Murciélago'/901793, l='MpServer', x=278,53, y=17,32, z=-113,63], sd['Murciélago'/898321, l='MpServer', x=143,22, y=25,00, z=-125,56], sd['Murciélago'/898323, l='MpServer', x=136,25, y=26,10, z=-126,28], os['entity.ItemFrame.name'/285526, l='MpServer', x=208,50, y=67,50, z=-63,06], os['entity.ItemFrame.name'/26695, l='MpServer', x=209,50, y=66,50, z=-71,94], os['entity.ItemFrame.name'/285550, l='MpServer', x=207,50, y=67,50, z=-63,06], os['entity.ItemFrame.name'/26735, l='MpServer', x=210,50, y=66,50, z=-71,94], os['entity.ItemFrame.name'/26650, l='MpServer', x=208,50, y=66,50, z=-71,94], sd['Murciélago'/1085065, l='MpServer', x=280,08, y=12,71, z=-107,26], os['entity.ItemFrame.name'/285644, l='MpServer', x=208,50, y=69,50, z=-63,06], os['entity.ItemFrame.name'/285638, l='MpServer', x=208,50, y=68,50, z=-63,06], os['entity.ItemFrame.name'/285650, l='MpServer', x=207,50, y=69,50, z=-63,06], os['entity.ItemFrame.name'/285653, l='MpServer', x=206,50, y=69,50, z=-63,06], os['entity.ItemFrame.name'/26777, l='MpServer', x=211,50, y=66,50, z=-71,94], os['entity.ItemFrame.name'/285595, l='MpServer', x=206,50, y=67,50, z=-63,06], os['entity.ItemFrame.name'/285613, l='MpServer', x=206,50, y=68,50, z=-63,06], os['entity.ItemFrame.name'/285623, l='MpServer', x=207,50, y=68,50, z=-63,06]]
	Retry entities: 0 total; []
	Server brand: vanilla
	Server type: Integrated singleplayer 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: Mac OS X (x86_64) version 10.8.4
	Java Version: 1.6.0_51, Apple Inc.
	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Apple Inc.
	Memory: 98198448 bytes (93 MB) / 290304000 bytes (276 MB) up to 1065025536 bytes (1015 MB)
	JVM Flags: 1 total; -Xmx1G
	AABB Pool Size: 578 (32368 bytes; 0 MB) allocated, 14 (784 bytes; 0 MB) used
	Suspicious classes: [com.ibm.icu.impl.UBiDiProps, Authenticate, ICUData, ...], [com.ibm.icu.lang.ECharacterCategory, ECharacterDirection, UCharacter], [com.ibm.icu.text.ArabicShapingException, Bidi, ImpTabPair, ...], [com.ibm.icu.util.ValueIterator, RangeValueIterator], [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: 12, tallocated: 94
	Launched Version: 13w36a
	LWJGL: 2.9.0
	OpenGL: AMD Radeon HD 6770M OpenGL Engine GL version 2.1 ATI-1.8.18, ATI Technologies Inc.
	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: 699 (39144 bytes; 0 MB) allocated, 51 (2856 bytes; 0 MB) used