Worlds will not load

Once you start to go into a world you will see it is loading normally but it will crash when the world is finally loaded
Crash report:

--- Minecraft Crash Report ----
// I feel sad now :(

Time: 7/5/13 8:56 PM
Description: Unexpected error

java.lang.NullPointerException
	at bfa.a(SourceFile:1334)
	at bet.a(SourceFile:810)
	at bet.b(SourceFile:693)
	at atn.S(SourceFile:685)
	at atn.d(SourceFile:618)
	at net.minecraft.client.main.Main.main(SourceFile:101)


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

-- Head --
Stacktrace:
	at bfa.a(SourceFile:1334)
	at bet.a(SourceFile:810)

-- Affected level --
Details:
	Level name: MpServer
	All players: 1 total; [bcx['Froste_10'/162, l='MpServer', x=-237.50, y=66.62, z=276.50]]
	Chunk stats: MultiplayerChunkCache: 0
	Level seed: 0
	Level generator: ID 00 - default, ver 1. Features enabled: false
	Level generator options: 
	Level spawn location: World: (-246,64,267), Chunk: (at 10,4,11 in -16,16; contains blocks -256,0,256 to -241,255,271), Region: (-1,0; contains chunks -32,0 to -1,31, blocks -512,0,0 to -1,255,511)
	Level time: 6 game time, 6 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; [bcx['Froste_10'/162, l='MpServer', x=-237.50, y=66.62, z=276.50]]
	Retry entities: 0 total; []
Stacktrace:
	at bcu.a(SourceFile:284)
	at atn.b(SourceFile:1743)
	at atn.d(SourceFile:632)
	at net.minecraft.client.main.Main.main(SourceFile:101)

-- System Details --
Details:
	Minecraft Version: 1.6.1
	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), Oracle Corporation
	Memory: 142509320 bytes (135 MB) / 247209984 bytes (235 MB) up to 1037959168 bytes (989 MB)
	JVM Flags: 1 total; -Xmx1G
	AABB Pool Size: 18 (1008 bytes; 0 MB) allocated, 18 (1008 bytes; 0 MB) used
	Suspicious classes: No suspicious classes found.
	IntCache: cache: 0, tcache: 0, allocated: 3, tallocated: 63
	Launched Version: 1.6.1
	LWJGL: 2.9.0
	OpenGL: Intel 965/963 Graphics Media Accelerator GL version 2.0.0 - Build 8.14.10.1930, Intel
	Is Modded: Probably not. Jar signature remains and client brand is untouched.
	Type: Client (map_client.txt)
	Resource Pack: Default
	Profiler Position: N/A (disabled)
	Vec3 Pool Size: 40 (2240 bytes; 0 MB) allocated, 40 (2240 bytes; 0 MB) used