While teleporting back from nether the game always crashes

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

Time: 2/8/13 11:10 AM
Description: Exception ticking world

java.lang.NullPointerException
at jq.c(SourceFile:206)
at jr.b(SourceFile:110)
at net.minecraft.server.MinecraftServer.t(SourceFile:462)
at net.minecraft.server.MinecraftServer.s(SourceFile:405)
at bkw.s(SourceFile:124)
at net.minecraft.server.MinecraftServer.run(SourceFile:339)
at hh.run(SourceFile:582)

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

– Head –
Stacktrace:
at jq.c(SourceFile:206)
at jr.b(SourceFile:110)

– Affected level –
Details:
Level name: Hitman's world!!! 😉
All players: 0 total; []
Chunk stats: ServerChunkCache: 258 Drop: 259
Level seed: -657831630479695843
Level generator: ID 00 - default, ver 1. Features enabled: false
Level generator options:
Level spawn location: World: (0,0,0), Chunk: (at 0,0,0 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)
Level time: 0 game time, 0 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: ~_ERROR~ NullPointerException: null
Stacktrace:
at net.minecraft.server.MinecraftServer.t(SourceFile:462)
at net.minecraft.server.MinecraftServer.s(SourceFile:405)
at bkw.s(SourceFile:124)
at net.minecraft.server.MinecraftServer.run(SourceFile:339)
at hh.run(SourceFile:582)

– 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: 183641448 bytes (175 MB) / 377552896 bytes (360 MB) up to 1908932608 bytes (1820 MB)
JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx2G
AABB Pool Size: 6034 (337904 bytes; 0 MB) allocated, 5634 (315504 bytes; 0 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: 1285 (71960 bytes; 0 MB) allocated, 1275 (71400 bytes; 0 MB) used
Player Count: 1 / 8; [ju['Hitman2110'/364, l='Hitman's world!!! 😉', x=-12.00, y=74.30, z=171.00]]
Type: Integrated Server (map_client.txt)
Is Modded: Probably not. Jar signature remains and both client + server brands are untouched.

Minecraft Crash Report ----
// Surprise! Haha. Well, this is awkward.

Time: 2/8/13 11:26 AM
Description: Exception ticking world

java.lang.NullPointerException
at jq.c(SourceFile:206)
at jr.b(SourceFile:110)
at net.minecraft.server.MinecraftServer.t(SourceFile:462)
at net.minecraft.server.MinecraftServer.s(SourceFile:405)
at bkw.s(SourceFile:124)
at net.minecraft.server.MinecraftServer.run(SourceFile:339)
at hh.run(SourceFile:582)

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

– Head –
Stacktrace:
at jq.c(SourceFile:206)
at jr.b(SourceFile:110)

– Affected level –
Details:
Level name: Hitman's world!!! 😉
All players: 0 total; []
Chunk stats: ServerChunkCache: 256 Drop: 257
Level seed: -657831630479695843
Level generator: ID 00 - default, ver 1. Features enabled: false
Level generator options:
Level spawn location: World: (0,0,0), Chunk: (at 0,0,0 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)
Level time: 0 game time, 0 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: ~_ERROR~ NullPointerException: null
Stacktrace:
at net.minecraft.server.MinecraftServer.t(SourceFile:462)
at net.minecraft.server.MinecraftServer.s(SourceFile:405)
at bkw.s(SourceFile:124)
at net.minecraft.server.MinecraftServer.run(SourceFile:339)
at hh.run(SourceFile:582)

– 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: 201680760 bytes (192 MB) / 411500544 bytes (392 MB) up to 1908932608 bytes (1820 MB)
JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx2G
AABB Pool Size: 6252 (350112 bytes; 0 MB) allocated, 5437 (304472 bytes; 0 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: 1464 (81984 bytes; 0 MB) allocated, 1421 (79576 bytes; 0 MB) used
Player Count: 1 / 8; [ju['Hitman2110'/364, l='Hitman's world!!! 😉', x=-12.00, y=74.01, z=171.00]]
Type: Integrated Server (map_client.txt)
Is Modded: Probably not. Jar signature remains and both client + server brands are untouched.

I think i should attach all the crash report

Crash report for the game

Duplicate of MC-3583 (Unresolved)