"Time: 4/3/14 3:02 PM
Description: Invalid Biome id

java.lang.NullPointerException: Invalid Biome id
at agy.a(SourceFile:82)
at agw.<init>(SourceFile:26)
at agv.a(SourceFile:52)
at agv.b(SourceFile:61)
at agy.a(SourceFile:61)
at aou.a(SourceFile:933)
at afy.a(SourceFile:114)
at afy.a(SourceFile:1045)
at bms.j(SourceFile:1343)
at bms.a(SourceFile:928)
at bms.b(SourceFile:814)
at azl.ah(SourceFile:784)
at azl.f(SourceFile:711)
at net.minecraft.client.main.Main.main(SourceFile:148)

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

– Head –
Stacktrace:
at agy.a(SourceFile:82)

– DownfallBlock –
Details:
biome id: 0
downfalls[] size: 256
x: 0
z: 0
w: 16
h: 16
Stacktrace:
at agy.a(SourceFile:82)
at agw.<init>(SourceFile:26)
at agv.a(SourceFile:52)
at agv.b(SourceFile:61)
at agy.a(SourceFile:61)
at aou.a(SourceFile:933)

– 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 afy.a(SourceFile:114)
at afy.a(SourceFile:1045)
at bms.j(SourceFile:1343)
at bms.a(SourceFile:928)

– Affected level –
Details:
Level name: MpServer
All players: 1 total; [bkl['durzanult'/1795860, l='MpServer', x=8.50, y=65.93, 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: (-244,64,252), Chunk: (at 12,4,12 in -16,15; contains blocks -256,0,240 to -241,255,255), Region: (-1,0; contains chunks -32,0 to -1,31, blocks -512,0,0 to -1,255,511)
Level time: 9 game time, 9 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: true. Cheats: false
Forced entities: 1 total; [bkl['durzanult'/1795860, l='MpServer', x=8.50, y=65.93, z=8.50]]
Retry entities: 0 total; []
Server brand: vanilla
Server type: Integrated singleplayer server
Stacktrace:
at bkg.a(SourceFile:289)
at azl.b(SourceFile:1947)
at azl.f(SourceFile:720)
at net.minecraft.client.main.Main.main(SourceFile:148)

– System Details –
Details:
Minecraft Version: 1.7.5
Operating System: Mac OS X (x86_64) version 10.9.2
Java Version: 1.6.0_65, Apple Inc.
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Apple Inc.
Memory: 135759048 bytes (129 MB) / 295768064 bytes (282 MB) up to 1065025536 bytes (1015 MB)
JVM Flags: 1 total; -Xmx1G
AABB Pool Size: 0 (0 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
IntCache: cache: 0, tcache: 18, allocated: 12, tallocated: 94
Launched Version: 1.7.5
LWJGL: 2.9.1
OpenGL: Intel HD Graphics 5000 OpenGL Engine GL version 2.1 INTEL-8.24.11, Intel Inc.
GL Caps: Using GL 1.3 multitexturing.
Using framebuffer objects because ARB_framebuffer_object is supported and separate blending is supported.
Anisotropic filtering is supported and maximum anisotropy is 16.
Shaders are available because OpenGL 2.1 is supported.

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: 0 (0 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
Anisotropic Filtering: Off (1)"

What I expected to happen was...:
I started up a hardcore map, and expected it to run smoothly

What actually happened was...:
The game crashed.

Steps to Reproduce:
1. Put a step by step guide on how to trigger the bug here
2. ...
3. ...