wen i try to play online on my original minecraft multyplayer give me a crash

---- Minecraft Crash Report ----
// This is a token for 1 free hug. Redeem at your nearest Mojangsta: _HUG~

Time: 12-11-2013 18:11
Description: Ticking screen

java.lang.NullPointerException: Ticking screen
at biv.a(SourceFile:589)
at hg.a(SourceFile:32)
at hg.a(SourceFile:13)
at ef.a(SourceFile:164)
at bbe.c(SourceFile:76)
at azd.o(SourceFile:1318)
at azd.ad(SourceFile:753)
at azd.e(SourceFile:704)
at net.minecraft.client.main.Main.main(SourceFile:103)

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

– Head –
Stacktrace:
at biv.a(SourceFile:589)
at hg.a(SourceFile:32)
at hg.a(SourceFile:13)
at ef.a(SourceFile:164)
at bbe.c(SourceFile:76)

– Affected screen –
Details:
Screen name: bbe
Stacktrace:
at azd.o(SourceFile:1318)
at azd.ad(SourceFile:753)
at azd.e(SourceFile:704)
at net.minecraft.client.main.Main.main(SourceFile:103)

– System Details –
Details:
Minecraft Version: 1.7.2
Operating System: Windows 8 (x86) version 6.2
Java Version: 1.7.0_40, Oracle Corporation
Java VM Version: Java HotSpot(TM) Client VM (mixed mode, sharing), Oracle Corporation
Memory: 37036368 bytes (35 MB) / 81551360 bytes (77 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: 0, tallocated: 0
Launched Version: 1.7.2
LWJGL: 2.9.0
OpenGL: ATI Radeon HD 4300/4500 Series GL version 3.3.11672 Compatibility Profile Context, ATI Technologies Inc.
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: ~_ERROR~ NullPointerException: null
Anisotropic Filtering: Off (1)