Bug Minecraft

Bonjour à tous, je suis sous Ubuntu version : 12.04 LTS.
J'ai un problème quand je lance Minecraft, je suis sous Java Runtime Environment 6.
Après le chargement de Minecraft il est écrit :


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

Minecraft has stopped running because it encountered a problem; Failed to start game

A full error report has been saved to /home/pop/.minecraft/crash-reports/crash-2012-11-30_20.59.43-client.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 6001c731 --------
Full report at:
/home/pop/.minecraft/crash-reports/crash-2012-11-30_20.59.43-client.txt
Please show that file to Mojang, NOT just this screen!

Generated 30/11/12 20:59

-- System Details --
Details:
Minecraft Version: 1.4.5
Operating System: Linux (amd64) version 3.2.0-32-generic
Java Version: 1.6.0_37, Sun Microsystems Inc.
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Sun Microsystems Inc.
Memory: 35429224 bytes (33 MB) / 60555264 bytes (57 MB) up to 898564096 bytes (856 MB)
JVM Flags: 0 total;
AABB Pool Size: 0 (0 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
Suspicious classes: No suspicious classes found.
IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
LWJGL: 2.4.2
OpenGL: ~~ERROR~~ NullPointerException: null
Is Modded: Probably not. Jar signature remains and client brand is untouched.
Type: Client (map_client.txt)
Texture Pack: ~~ERROR~~ NullPointerException: null
Profiler Position: N/A (disabled)
Vec3 Pool Size: ~~ERROR~~ NullPointerException: null[failed to get system properties (java.lang.NullPointerException)]


org.lwjgl.LWJGLException: X Error - disp: 0x7f9d60007a50 serial: 31 error: BadRequest (invalid request code or no such operation) request_code: 154 minor_code: 14
at org.lwjgl.opengl.LinuxDisplay.globalErrorHandler(LinuxDisplay.java:268)
at org.lwjgl.opengl.LinuxDisplayPeerInfo.initDefaultPeerInfo(Native Method)
at org.lwjgl.opengl.LinuxDisplayPeerInfo.<init>(LinuxDisplayPeerInfo.java:52)
at org.lwjgl.opengl.LinuxDisplay.createPeerInfo(LinuxDisplay.java:684)
at org.lwjgl.opengl.Display.create(Display.java:854)
at org.lwjgl.opengl.Display.create(Display.java:784)
at org.lwjgl.opengl.Display.create(Display.java:765)
at net.minecraft.client.Minecraft.a(SourceFile:232)
at net.minecraft.client.Minecraft.run(SourceFile:515)
at java.lang.Thread.run(Thread.java:662)
--- END ERROR REPORT dc9d566b ----------


Merci de m'aider.