Constant crash: mojira issue: MC-3583 , Description: Exception ticking world

Hello, after an hour of this I give up. MC will crash every 4 minutes regardless of what I do. I've tried:

• running to a different biome and waiting it out

• disabling all gfx settings and sounds

• minimized and fullscreen and big windowed

• uninstalled and reinstalled

• deleted .minecraft (minus the saved world), then reinstalled MC

• disabled all background programs

I don't know anything about java and am incapable of fixing this myself. I've no mods at all, not changed anything at all. I just know that my world is broken and I can't play MC with the missus so she's also a bit grumpy with this whole situation. Please find 2 files of 2 separate crashes. Thank you for any help.

Minecraft Crash Report ----
// You should try our sister game, Minceraft!

Time: 2014-03-10 00:09
Description: Exception ticking world

java.lang.NullPointerException: Exception ticking world
at mr.d(SourceFile:204)
at ms.b(SourceFile:119)
at net.minecraft.server.MinecraftServer.v(SourceFile:504)
at net.minecraft.server.MinecraftServer.u(SourceFile:443)
at btq.u(SourceFile:117)
at net.minecraft.server.MinecraftServer.run(SourceFile:359)
at lh.run(SourceFile:618)

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

– Head –
Stacktrace:
at mr.d(SourceFile:204)
at ms.b(SourceFile:119)

– Affected level –
Details:
Level name: Land of Gus
All players: 1 total; [mv['TooNu'/301, l='Land of Gus', x=-228,92, y=80,02, z=1520,70]]
Chunk stats: ServerChunkCache: 643 Drop: 82
Level seed: 996680995
Level generator: ID 00 - default, ver 1. Features enabled: true
Level generator options:
Level spawn location: World: (200,64,172), Chunk: (at 8,4,12 in 12,10; contains blocks 192,0,160 to 207,255,175), Region: (0,0; contains chunks 0,0 to 31,31, blocks 0,0,0 to 511,255,511)
Level time: 21164606 game time, 21372593 day time
Level dimension: 0
Level storage version: 0x04ABD - Anvil
Level weather: Rain time: 38665 (now: false), thunder time: 6002 (now: true)
Level game mode: Game mode: survival (ID 0). Hardcore: false. Cheats: false
Stacktrace:
at net.minecraft.server.MinecraftServer.v(SourceFile:504)
at net.minecraft.server.MinecraftServer.u(SourceFile:443)
at btq.u(SourceFile:117)
at net.minecraft.server.MinecraftServer.run(SourceFile:359)
at lh.run(SourceFile:618)

– System Details –
Details:
Minecraft Version: 1.7.5
Operating System: Windows 7 (x86) version 6.1
Java Version: 1.7.0_51, Oracle Corporation
Java VM Version: Java HotSpot(TM) Client VM (mixed mode, sharing), Oracle Corporation
Memory: 105493296 bytes (100 MB) / 352931840 bytes (336 MB) up to 518979584 bytes (494 MB)
JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx512M
AABB Pool Size: 0 (0 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
IntCache: cache: 0, tcache: 0, allocated: 13, tallocated: 95
Profiler Position: N/A (disabled)
Vec3 Pool Size: 0 (0 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
Player Count: 1 / 8; [mv['TooNu'/301, l='Land of Gus', x=-228,92, y=80,02, z=1520,70]]
Type: Integrated Server (map_client.txt)
Is Modded: Probably not. Jar signature remains and both client + server brands are untouched.