Hopper: java.lang.NullPointerException

This is an automatically generated report based from the following crash: http://hopper.minecraft.net/crashes/minecraft/MCX-197134/

Crash:

java.lang.NullPointerException
	at aeh.a(SourceFile:82)

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

---- Minecraft Crash Report ----
// Don't do that.

Time: 20/09/13 17:54
Description: Invalid Biome id

java.lang.NullPointerException
	at aeh.a(SourceFile:82)
	at aef.<init>(SourceFile:26)
	at aee.a(SourceFile:52)
	at aee.b(SourceFile:61)
	at aeh.a(SourceFile:61)
	at afk.a(SourceFile:930)
	at ade.a(SourceFile:103)
	at ade.a(SourceFile:1029)
	at bii.i(SourceFile:1316)
	at bii.a(SourceFile:912)
	at bii.b(SourceFile:807)
	at awp.aa(SourceFile:754)
	at awp.e(SourceFile:677)
	at net.minecraft.client.main.Main.main(SourceFile:104)


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

-- Head --
Stacktrace:
	at aeh.a(SourceFile:82)

-- DownfallBlock --
Details:
	downfalls[] size: 256
	x: 0
	z: 0
	w: 16
	h: 16
Stacktrace:
	at aeh.a(SourceFile:82)
	at aef.<init>(SourceFile:26)
	at aee.a(SourceFile:52)
	at aee.b(SourceFile:61)
	at aeh.a(SourceFile:61)
	at afk.a(SourceFile:930)

-- Coordinates of biome request --
Details:
	Location: World: (8,0,8), Chunk: (at 8,0,8 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)
Stacktrace:
	at ade.a(SourceFile:103)
	at ade.a(SourceFile:1029)
	at bii.i(SourceFile:1316)
	at bii.a(SourceFile:912)

-- Affected level --
Details:
	Level name: MpServer
	All players: 1 total; [bgh['balleva'/83, l='MpServer', x=8,50, y=66,62, z=8,50]]
	Chunk stats: MultiplayerChunkCache: 0, 0
	Level seed: 0
	Level generator: ID 00 - default, ver 1. Features enabled: false
	Level generator options: 
	Level spawn location: World: (-302,66,117), Chunk: (at 2,4,5 in -19,7; contains blocks -304,0,112 to -289,255,127), Region: (-1,0; contains chunks -32,0 to -1,31, blocks -512,0,0 to -1,255,511)
	Level time: 7614739 game time, 7812410 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: 1 total; [bgh['balleva'/83, l='MpServer', x=8,50, y=66,62, z=8,50]]
	Retry entities: 0 total; []
	Server brand: vanilla
	Server type: Integrated singleplayer server
Stacktrace:
	at bgc.a(SourceFile:297)
	at awp.b(SourceFile:1874)
	at awp.e(SourceFile:686)
	at net.minecraft.client.main.Main.main(SourceFile:104)

-- System Details --
Details:
	Minecraft Version: 13w38c
	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, sharing), Oracle Corporation
	Memory: 109732376 bytes (104 MB) / 190013440 bytes (181 MB) up to 518979584 bytes (494 MB)
	JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx512M
	AABB Pool Size: 10003 (560168 bytes; 0 MB) allocated, 10003 (560168 bytes; 0 MB) used
	IntCache: cache: 4, tcache: 50, allocated: 8, tallocated: 62
	Launched Version: 13w38c
	LWJGL: 2.9.0
	OpenGL: GeForce GTX 260/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 Packs: []
	Current Language: Français (France)
	Profiler Position: N/A (disabled)
	Vec3 Pool Size: 12 (672 bytes; 0 MB) allocated, 12 (672 bytes; 0 MB) used

You can see this full report at http://hopper.minecraft.net/crashes/minecraft/MCX-197134/12626707/