Minecraft Has Crashed Error

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

Minecraft has stopped running because it encountered a problem.

If you wish to report this, please copy this entire text and email it to support@mojang.com.
Please include a description of what you did when the error occured.



--- BEGIN ERROR REPORT a1dce528 --------
Generated 11/30/10 7:01 PM

Minecraft: Minecraft Alpha v1.2.4_01
OS: Linux (i386) version 2.6.35-22-generic
Java: 1.6.0_22, Sun Microsystems Inc.
VM: Java HotSpot(TM) Client VM (mixed mode, sharing), Sun Microsystems Inc.
LWJGL: 2.4.2
[failed to get system properties (java.lang.NullPointerException)]

java.lang.IllegalStateException: Only one LWJGL context may be instantiated at any one time.
	at org.lwjgl.opengl.Display.create(Display.java:846)
	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:197)
	at net.minecraft.client.Minecraft.run(SourceFile:559)
	at java.lang.Thread.run(Unknown Source)
--- END ERROR REPORT 7c1e9436 ----------