Minecraft has crashed!
----------------------

Minecraft has stopped running because it encountered a problem; Exception in server tick loop

A full error report has been saved to /Users/1500212/Library/Application Support/minecraft/crash-reports/crash-2013-01-11_15.15.10-server.txt - Please include a copy of that file (Not this screen!) if you report this crash to anyone; without it, they will not be able to help fix the crash

— BEGIN ERROR REPORT bdecb7d5 --------
Full report at:
/Users/1500212/Library/Application Support/minecraft/crash-reports/crash-2013-01-11_15.15.10-server.txt
Please show that file to Mojang, NOT just this screen!

Generated 1/11/13 3:15 PM

– System Details –
Details:
Minecraft Version: 13w02a
Operating System: Mac OS X (i386) version 10.6.8
Java Version: 1.6.0_37, Apple Inc.
Java VM Version: Java HotSpot(TM) Client VM (mixed mode), Apple Inc.
Memory: 394513024 bytes (376 MB) / 550305792 bytes (524 MB) up to 1070399488 bytes (1020 MB)
JVM Flags: 3 total; -Xbootclasspath/a:/System/Library/PrivateFrameworks/JavaApplicationLauncher.framework/Resources/LauncherSupport.jar -Xms512M -Xmx1024M
AABB Pool Size: 148788 (8332128 bytes; 7 MB) allocated, 148788 (8332128 bytes; 7 MB) used
Suspicious classes: No suspicious classes found.
IntCache: cache: 0, tcache: 0, allocated: 1, tallocated: 63
Profiler Position: N/A (disabled)
Vec3 Pool Size: 13282 (743792 bytes; 0 MB) allocated, 13282 (743792 bytes; 0 MB) used
Player Count: 0 / 8; []
Type: Integrated Server (map_client.txt)
Is Modded: Probably not. Jar signature remains and both client + server brands are untouched.

java.lang.NullPointerException
at cf.b(SourceFile:103)
at cf.a(SourceFile:35)
at iv.b(SourceFile:436)
at gm.a(SourceFile:72)
at bfg.b(SourceFile:73)
at net.minecraft.server.MinecraftServer.r(SourceFile:762)
at net.minecraft.server.MinecraftServer.q(SourceFile:679)
at bfd.q(SourceFile:117)
at net.minecraft.server.MinecraftServer.run(SourceFile:613)
at fy.run(SourceFile:849)
— END ERROR REPORT 7eb1fa19 ----------
______________________________________________________________________________

---- Minecraft Crash Report ----
// Ouch. That hurt

Time: 1/11/13 3:15 PM
Description: Ticking entity

java.lang.NullPointerException
at cf.b(SourceFile:103)
at cf.a(SourceFile:35)
at iv.b(SourceFile:436)
at iq.l_(SourceFile:147)
at yn.a(SourceFile:1312)
at in.a(SourceFile:480)
at yn.g(SourceFile:1290)
at yn.h(SourceFile:1197)
at in.h(SourceFile:374)
at net.minecraft.server.MinecraftServer.r(SourceFile:744)
at net.minecraft.server.MinecraftServer.q(SourceFile:679)
at bfd.q(SourceFile:117)
at net.minecraft.server.MinecraftServer.run(SourceFile:613)
at fy.run(SourceFile:849)

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

– Head –
Stacktrace:
at cf.b(SourceFile:103)
at cf.a(SourceFile:35)
at iv.b(SourceFile:436)
at iq.l_(SourceFile:147)
at yn.a(SourceFile:1312)
at in.a(SourceFile:480)
at yn.g(SourceFile:1290)

– Entity being ticked –
Details:
Entity Type: null (iq)
Entity ID: 16255
Name: Player
Exact location: -371.51, 72.17, 81.30
Block location: World: (-372,72,81), Chunk: (at 12,4,1 in -24,5; contains blocks -384,0,80 to -369,255,95), Region: (-1,0; contains chunks -32,0 to -1,31, blocks -512,0,0 to -1,255,511)
Momentum: 0.00, -0.30, 0.00
Stacktrace:
at yn.h(SourceFile:1197)
at in.h(SourceFile:374)

– Affected level –
Details:
Level name: 1.8.1 Minecraft Reference
All players: 1 total; [iq['Player'/16255, l='1.8.1 Minecraft Reference', x=-371.51, y=72.17, z=81.30]]
Chunk stats: ServerChunkCache: 897 Drop: 0
Level seed: -7711547331594155648
Level generator: ID 00 - default, ver 1. Features enabled: true
Level generator options:
Level spawn location: World: (-220,64,254), Chunk: (at 4,4,14 in -14,15; contains blocks -224,0,240 to -209,255,255), Region: (-1,0; contains chunks -32,0 to -1,31, blocks -512,0,0 to -1,255,511)
Level time: 5288828 game time, 5643076 day time
Level dimension: 0
Level storage version: 0x04ABD - Anvil
Level weather: Rain time: 17145 (now: true), thunder time: 157978 (now: false)
Level game mode: Game mode: survival (ID 0). Hardcore: false. Cheats: false
Stacktrace:
at net.minecraft.server.MinecraftServer.r(SourceFile:744)
at net.minecraft.server.MinecraftServer.q(SourceFile:679)
at bfd.q(SourceFile:117)
at net.minecraft.server.MinecraftServer.run(SourceFile:613)
at fy.run(SourceFile:849)

– System Details –
Details:
Minecraft Version: 13w02a
Operating System: Mac OS X (i386) version 10.6.8
Java Version: 1.6.0_37, Apple Inc.
Java VM Version: Java HotSpot(TM) Client VM (mixed mode), Apple Inc.
Memory: 423553152 bytes (403 MB) / 550305792 bytes (524 MB) up to 1070399488 bytes (1020 MB)
JVM Flags: 3 total; -Xbootclasspath/a:/System/Library/PrivateFrameworks/JavaApplicationLauncher.framework/Resources/LauncherSupport.jar -Xms512M -Xmx1024M
AABB Pool Size: 206361 (11556216 bytes; 11 MB) allocated, 206361 (11556216 bytes; 11 MB) used
Suspicious classes: No suspicious classes found.
IntCache: cache: 0, tcache: 0, allocated: 1, tallocated: 63
Profiler Position: N/A (disabled)
Vec3 Pool Size: 13163 (737128 bytes; 0 MB) allocated, 13150 (736400 bytes; 0 MB) used
Player Count: 1 / 8; [iq['Player'/16255, l='1.8.1 Minecraft Reference', x=-371.51, y=72.17, z=81.30]]
Type: Integrated Server (map_client.txt)
Is Modded: Probably not. Jar signature remains and both client + server brands are untouched.

Loaded up my world, and it had trouble loading chunks. I force quit Minecraft, and reloaded it. No longer works, and it crashes Minecraft. Above is the two error reports. Linked here: http://dl.dropbox.com/u/102891025/World%201.zip is the world in a .zip file.