Hopper: java.lang.NullPointerException at on.c(SourceFile:87)

This is an automatically generated report based from the following crash: http://hopper.minecraft.net/crashes/minecraft/MCX-13997/

Crash:

java.lang.NullPointerException
	at on.c(SourceFile:87)
	at oe.aI(SourceFile:411)
	at oe.x(SourceFile:214)
	at of.x(SourceFile:128)
	at nm.l_(SourceFile:278)
	at oe.l_(SourceFile:1149)
	at of.l_(SourceFile:169)
	at rn.l_(SourceFile:107)
	at abv.a(SourceFile:1349)
	at abv.g(SourceFile:1327)

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

---- Minecraft Crash Report ----
// Don't be sad, have a hug! <3

Time: 3/08/13 14:49
Description: Ticking entity

java.lang.NullPointerException
	at on.c(SourceFile:87)
	at oe.aI(SourceFile:411)
	at oe.x(SourceFile:214)
	at of.x(SourceFile:128)
	at nm.l_(SourceFile:278)
	at oe.l_(SourceFile:1149)
	at of.l_(SourceFile:169)
	at rn.l_(SourceFile:107)
	at abv.a(SourceFile:1349)
	at abv.g(SourceFile:1327)
	at abv.h(SourceFile:1234)
	at ats.k(SourceFile:1380)
	at ats.S(SourceFile:663)
	at ats.d(SourceFile:619)
	at net.minecraft.client.main.Main.main(SourceFile:101)


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

-- Head --
Stacktrace:
	at on.c(SourceFile:87)
	at oe.aI(SourceFile:411)
	at oe.x(SourceFile:214)
	at of.x(SourceFile:128)
	at nm.l_(SourceFile:278)
	at oe.l_(SourceFile:1149)
	at of.l_(SourceFile:169)
	at rn.l_(SourceFile:107)
	at abv.a(SourceFile:1349)
	at abv.g(SourceFile:1327)

-- Entity being ticked --
Details:
	Entity Type: Bat (rn)
	Entity ID: 1192249
	Entity Name: Murciélago
	Entity's Exact location: -137,53, 17,51, 282,53
	Entity's Block location: World: (-138,17,282), Chunk: (at 6,1,10 in -9,17; contains blocks -144,0,272 to -129,255,287), Region: (-1,0; contains chunks -32,0 to -1,31, blocks -512,0,0 to -1,255,511)
	Entity's Momentum: 0,00, -0,11, 0,00
Stacktrace:
	at abv.h(SourceFile:1234)

-- Affected level --
Details:
	Level name: MpServer
	All players: 1 total; [bdf['McNelo'/199, l='MpServer', x=-140,30, y=33,62, z=344,30]]
	Chunk stats: MultiplayerChunkCache: 441
	Level seed: 0
	Level generator: ID 00 - default, ver 1. Features enabled: false
	Level generator options: 
	Level spawn location: World: (-144,64,226), Chunk: (at 0,4,2 in -9,14; contains blocks -144,0,224 to -129,255,239), Region: (-1,0; contains chunks -32,0 to -1,31, blocks -512,0,0 to -1,255,511)
	Level time: 8358422 game time, 8779223 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: 89 total; [tq['Esqueleto'/534463, l='MpServer', x=-148,69, y=30,85, z=330,69], ry['Oveja'/467713, l='MpServer', x=-173,50, y=79,00, z=417,50], rn['Murciélago'/1056855, l='MpServer', x=-121,59, y=25,10, z=327,78], tq['Esqueleto'/479444, l='MpServer', x=-148,70, y=29,00, z=325,30], rn['Murciélago'/1185392, l='MpServer', x=-86,13, y=57,02, z=398,94], tq['Esqueleto'/485902, l='MpServer', x=-148,70, y=29,00, z=325,30], tq['Esqueleto'/493085, l='MpServer', x=-148,30, y=29,00, z=325,30], sb['Calamar'/484849, l='MpServer', x=-146,50, y=39,00, z=322,49], rn['Murciélago'/1192272, l='MpServer', x=-155,50, y=62,00, z=379,53], rx['Cerdo'/22, l='MpServer', x=-195,28, y=62,02, z=348,56], tq['Esqueleto'/503024, l='MpServer', x=-148,30, y=29,00, z=325,30], tq['Esqueleto'/484244, l='MpServer', x=-148,30, y=29,00, z=325,30], tq['Esqueleto'/1190092, l='MpServer', x=-110,50, y=73,00, z=306,50], tv['Zombi'/997087, l='MpServer', x=-132,69, y=20,01, z=322,31], tq['Esqueleto'/548601, l='MpServer', x=-148,69, y=30,06, z=327,28], te['Creeper'/1182103, l='MpServer', x=-150,59, y=68,00, z=419,94], tq['Esqueleto'/1148260, l='MpServer', x=-116,50, y=21,85, z=345,69], tv['Zombi'/1190107, l='MpServer', x=-84,50, y=69,00, z=326,50], tv['Zombi'/1190106, l='MpServer', x=-86,50, y=69,00, z=325,50], tv['Zombi'/1190105, l='MpServer', x=-87,50, y=69,00, z=325,50], tv['Zombi'/1190104, l='MpServer', x=-88,50, y=69,00, z=325,50], tq['Esqueleto'/559054, l='MpServer', x=-148,69, y=30,00, z=329,21], tq['Esqueleto'/553587, l='MpServer', x=-148,31, y=30,03, z=332,68], te['Creeper'/967788, l='MpServer', x=-158,97, y=33,00, z=339,47], tr['Slime'/79, l='MpServer', x=-138,69, y=17,14, z=283,69], tq['Esqueleto'/1186804, l='MpServer', x=-96,50, y=63,00, z=333,50], tq['Esqueleto'/565644, l='MpServer', x=-148,31, y=30,28, z=331,91], tq['Esqueleto'/520935, l='MpServer', x=-148,70, y=29,00, z=325,30], tq['Esqueleto'/1192767, l='MpServer', x=-137,50, y=74,00, z=406,50], tq['Esqueleto'/526678, l='MpServer', x=-148,50, y=31,16, z=335,29], tq['Esqueleto'/1192766, l='MpServer', x=-138,50, y=74,00, z=405,50], tq['Esqueleto'/614331, l='MpServer', x=-148,70, y=31,21, z=340,70], rn['Murciélago'/483163, l='MpServer', x=-152,59, y=15,10, z=336,25], sb['Calamar'/865672, l='MpServer', x=-139,53, y=39,00, z=319,96], rn['Murciélago'/639810, l='MpServer', x=-116,25, y=17,10, z=330,59], sb['Calamar'/865669, l='MpServer', x=-139,47, y=38,00, z=320,00], sb['Calamar'/865670, l='MpServer', x=-141,50, y=38,00, z=319,50], rn['Murciélago'/1179496, l='MpServer', x=-143,41, y=61,10, z=409,09], tq['Esqueleto'/508600, l='MpServer', x=-148,30, y=29,00, z=325,30], tq['Esqueleto'/476359, l='MpServer', x=-148,30, y=29,00, z=325,30], tq['Esqueleto'/616625, l='MpServer', x=-148,70, y=31,00, z=340,70], tq['Esqueleto'/536966, l='MpServer', x=-148,30, y=29,00, z=325,30], rn['Murciélago'/1192249, l='MpServer', x=-137,53, y=17,51, z=282,53], tq['Esqueleto'/524536, l='MpServer', x=-148,30, y=29,00, z=325,30], tq['Esqueleto'/1185521, l='MpServer', x=-135,50, y=73,00, z=401,50], tq['Esqueleto'/606110, l='MpServer', x=-148,30, y=29,00, z=325,30], sb['Calamar'/499236, l='MpServer', x=-137,47, y=36,19, z=317,47], sb['Calamar'/499237, l='MpServer', x=-137,48, y=36,00, z=318,36], tr['Slime'/473059, l='MpServer', x=-95,61, y=38,00, z=299,31], tq['Esqueleto'/619229, l='MpServer', x=-147,30, y=32,00, z=340,30], tv['Zombi'/731856, l='MpServer', x=-131,76, y=20,32, z=322,30], te['Creeper'/731860, l='MpServer', x=-135,69, y=20,00, z=320,31], tq['Esqueleto'/515229, l='MpServer', x=-148,31, y=30,53, z=333,47], tq['Esqueleto'/579629, l='MpServer', x=-148,30, y=30,72, z=328,24], tv['Zombi'/750992, l='MpServer', x=-148,47, y=10,00, z=338,50], tq['Esqueleto'/513557, l='MpServer', x=-148,30, y=29,00, z=325,30], tq['Esqueleto'/505324, l='MpServer', x=-148,69, y=29,00, z=325,31], te['Creeper'/761948, l='MpServer', x=-131,69, y=20,71, z=324,69], te['Creeper'/681902, l='MpServer', x=-163,50, y=28,00, z=336,50], tq['Esqueleto'/529188, l='MpServer', x=-148,30, y=29,00, z=325,30], rn['Murciélago'/827050, l='MpServer', x=-154,44, y=18,10, z=342,75], rn['Murciélago'/467074, l='MpServer', x=-123,44, y=35,10, z=325,75], te['Creeper'/993778, l='MpServer', x=-146,31, y=12,00, z=338,50], rn['Murciélago'/772475, l='MpServer', x=-131,84, y=9,10, z=327,75], rn['Murciélago'/703947, l='MpServer', x=-137,28, y=22,10, z=322,00], rn['Murciélago'/703945, l='MpServer', x=-124,28, y=21,10, z=325,75], rn['Murciélago'/772476, l='MpServer', x=-132,75, y=9,10, z=328,75], ry['Oveja'/467455, l='MpServer', x=-173,50, y=76,00, z=415,50], tq['Esqueleto'/609127, l='MpServer', x=-148,16, y=32,00, z=340,30], tq['Esqueleto'/569346, l='MpServer', x=-148,70, y=29,00, z=325,30], ry['Oveja'/459690, l='MpServer', x=-184,19, y=70,00, z=390,84], rx['Cerdo'/459688, l='MpServer', x=-200,50, y=67,00, z=394,59], ry['Oveja'/459689, l='MpServer', x=-179,38, y=71,00, z=395,53], bdf['McNelo'/199, l='MpServer', x=-140,30, y=33,62, z=344,30], rn['Murciélago'/822517, l='MpServer', x=-126,44, y=22,10, z=323,38], tq['Esqueleto'/1158499, l='MpServer', x=-152,00, y=10,88, z=340,56], tf['Enderman'/531194, l='MpServer', x=-118,91, y=24,00, z=328,56], tq['Esqueleto'/1186377, l='MpServer', x=-64,50, y=65,00, z=407,50], tq['Esqueleto'/542609, l='MpServer', x=-148,30, y=29,00, z=325,30], rx['Cerdo'/459686, l='MpServer', x=-200,84, y=64,00, z=369,09], rx['Cerdo'/459687, l='MpServer', x=-192,50, y=70,00, z=395,50], te['Creeper'/1185673, l='MpServer', x=-155,50, y=58,00, z=394,50], tq['Esqueleto'/468097, l='MpServer', x=-127,31, y=25,00, z=328,69], tq['Esqueleto'/468098, l='MpServer', x=-126,69, y=25,00, z=325,84], tq['Esqueleto'/488964, l='MpServer', x=-148,30, y=29,00, z=325,30], ts['Araña'/1186157, l='MpServer', x=-89,16, y=71,00, z=317,00], tq['Esqueleto'/572895, l='MpServer', x=-148,70, y=30,64, z=328,31], tq['Esqueleto'/498437, l='MpServer', x=-148,30, y=29,00, z=325,30], tq['Esqueleto'/1180112, l='MpServer', x=-75,50, y=63,00, z=354,50]]
	Retry entities: 0 total; []
	Server brand: vanilla
	Server type: Integrated singleplayer server
Stacktrace:
	at bda.a(SourceFile:284)
	at ats.b(SourceFile:1761)
	at ats.d(SourceFile:628)
	at net.minecraft.client.main.Main.main(SourceFile:101)

-- System Details --
Details:
	Minecraft Version: 1.6.2
	Operating System: Windows 7 (amd64) version 6.1
	Java Version: 1.7.0_21, Oracle Corporation
	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
	Memory: 80208264 bytes (76 MB) / 398983168 bytes (380 MB) up to 954466304 bytes (910 MB)
	JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx1G
	AABB Pool Size: 5066 (283696 bytes; 0 MB) allocated, 1124 (62944 bytes; 0 MB) used
	Suspicious classes: No suspicious classes found.
	IntCache: cache: 0, tcache: 0, allocated: 3, tallocated: 63
	Launched Version: 1.6.2
	LWJGL: 2.9.0
	OpenGL: GeForce GTS 250/PCIe/SSE2 GL version 3.3.0, NVIDIA Corporation
	Is Modded: Probably not. Jar signature remains and client brand is untouched.
	Type: Client (map_client.txt)
	Resource Pack: Default
	Current Language: Español (España)
	Profiler Position: N/A (disabled)
	Vec3 Pool Size: 909 (50904 bytes; 0 MB) allocated, 411 (23016 bytes; 0 MB) used

You can see this full report at http://hopper.minecraft.net/crashes/minecraft/MCX-13997/238453/