Hopper: java.lang.NullPointerException

This is an automatically generated report based from the following crash: http://hopper.minecraft.net/crashes/minecraft/MCX-84878/

Crash:

java.lang.NullPointerException
	at ack.a(SourceFile:110)
	at ack.h(SourceFile:234)
	at bln.a(SourceFile:22)
	at bln.a(SourceFile:17)
	at bln.a(SourceFile:12)

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

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

Time: 6-9-13 20:35
Description: Rendering Tile Entity

java.lang.NullPointerException
	at ack.a(SourceFile:110)
	at ack.h(SourceFile:234)
	at bln.a(SourceFile:22)
	at bln.a(SourceFile:17)
	at bln.a(SourceFile:12)
	at bls.a(SourceFile:106)
	at bls.a(SourceFile:98)
	at bhv.a(SourceFile:334)
	at bho.a(SourceFile:848)
	at bho.b(SourceFile:697)
	at awb.V(SourceFile:713)
	at awb.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 ack.a(SourceFile:110)
	at ack.h(SourceFile:234)
	at bln.a(SourceFile:22)
	at bln.a(SourceFile:17)
	at bln.a(SourceFile:12)

-- Tile Entity Details --
Details:
	Name: MobSpawner // auo
	Block type: ID #52 (tile.mobSpawner // arl)
	Block data value: 0 / 0x0 / 0b0000
	Block location: World: (-66,64,52), Chunk: (at 14,4,4 in -5,3; contains blocks -80,0,48 to -65,255,63), Region: (-1,0; contains chunks -32,0 to -1,31, blocks -512,0,0 to -1,255,511)
	Actual block type: ID #52 (tile.mobSpawner // arl)
	Actual block data value: 0 / 0x0 / 0b0000
Stacktrace:
	at bls.a(SourceFile:106)
	at bls.a(SourceFile:98)
	at bhv.a(SourceFile:334)
	at bho.a(SourceFile:848)

-- Affected level --
Details:
	Level name: MpServer
	All players: 1 total; [bfn['Nexion'/401726, l='MpServer', x=-70,29, y=65,86, z=44,35]]
	Chunk stats: MultiplayerChunkCache: 70, 70
	Level seed: 0
	Level generator: ID 01 - flat, ver 0. Features enabled: false
	Level generator options: 
	Level spawn location: World: (-86,64,63), Chunk: (at 10,4,15 in -6,3; contains blocks -96,0,48 to -81,255,63), Region: (-1,0; contains chunks -32,0 to -1,31, blocks -512,0,0 to -1,255,511)
	Level time: 5437 game time, 2045 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: 23 total; [uk['Spider'/401687, l='MpServer', x=-122,13, y=64,00, z=-1,91], uk['Spider'/401716, l='MpServer', x=-6,91, y=64,00, z=61,06], sf['Chicken'/401685, l='MpServer', x=-142,50, y=64,00, z=97,50], tj['item.item.rottenFlesh'/401684, l='MpServer', x=-133,47, y=64,13, z=79,47], sn['Pig'/401713, l='MpServer', x=-9,97, y=64,00, z=18,91], sn['Pig'/401712, l='MpServer', x=-4,81, y=64,00, z=27,66], sn['Pig'/401715, l='MpServer', x=-4,19, y=64,00, z=25,31], sn['Pig'/401714, l='MpServer', x=-1,28, y=64,00, z=29,81], tw['Creeper'/401695, l='MpServer', x=-99,50, y=64,00, z=-7,50], sn['Pig'/401691, l='MpServer', x=-126,16, y=64,00, z=15,16], sn['Pig'/401690, l='MpServer', x=-125,50, y=64,00, z=12,81], sn['Pig'/401689, l='MpServer', x=-125,50, y=64,00, z=11,22], sn['Pig'/401688, l='MpServer', x=-127,50, y=64,00, z=12,22], tj['item.item.rottenFlesh'/401700, l='MpServer', x=-90,84, y=64,13, z=83,16], tw['Creeper'/401701, l='MpServer', x=-77,91, y=64,00, z=29,66], tw['Creeper'/401702, l='MpServer', x=-64,63, y=64,00, z=23,00], tw['Creeper'/401696, l='MpServer', x=-111,13, y=64,00, z=50,84], uk['Spider'/401697, l='MpServer', x=-98,81, y=64,00, z=91,38], tw['Creeper'/401699, l='MpServer', x=-91,34, y=64,00, z=76,09], tj['item.item.arrow'/401709, l='MpServer', x=-28,91, y=64,13, z=47,81], tj['item.item.bone'/401710, l='MpServer', x=-30,19, y=64,13, z=47,50], bfn['Nexion'/401726, l='MpServer', x=-70,29, y=65,86, z=44,35], tj['item.item.rottenFlesh'/401706, l='MpServer', x=-47,63, y=64,13, z=106,00]]
	Retry entities: 0 total; []
	Server brand: vanilla
	Server type: Integrated singleplayer server
Stacktrace:
	at bfi.a(SourceFile:285)
	at awb.b(SourceFile:1813)
	at awb.e(SourceFile:651)
	at net.minecraft.client.main.Main.main(SourceFile:103)

-- System Details --
Details:
	Minecraft Version: 13w36b
	Operating System: Windows 8 (x86) version 6.2
	Java Version: 1.7.0_25, Oracle Corporation
	Java VM Version: Java HotSpot(TM) Client VM (mixed mode, sharing), Oracle Corporation
	Memory: 248206400 bytes (236 MB) / 518979584 bytes (494 MB) up to 518979584 bytes (494 MB)
	JVM Flags: 1 total; -Xmx512M
	AABB Pool Size: 19334 (1082704 bytes; 1 MB) allocated, 659 (36904 bytes; 0 MB) used
	IntCache: cache: 0, tcache: 0, allocated: 13, tallocated: 95
	Launched Version: 13w36b
	LWJGL: 2.9.0
	OpenGL: GeForce 710M/PCIe/SSE2 GL version 4.2.0, NVIDIA Corporation
	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: 687 (38472 bytes; 0 MB) allocated, 87 (4872 bytes; 0 MB) used

You can see this full report at http://hopper.minecraft.net/crashes/minecraft/MCX-84878/8400235/