Hum I don't see any GL11.glCallList in your code.
The exception trace indeed indicates that __result is null. The only situation this can happen is if nglMapBufferARB returns null. The NPE is not in nglMapBufferARB but in your own code therefore.
The code pasted is LWJGL code

To find out why nglMapBufferARB returns null the easiest way is to associate the lwjgl.jar with the LWJGL source and debug into it and see what's going on.
Did it and indeed __result is null, but since it is compiled code afterwards... I can't continue to debug.
The NullPointerException is indeed an LWJGL bug, there should be a null check before the .order call. There must also be a problem with your code for glMapBuffer to return null though. Check the GL error after the MapBuffer call, is it an OUT_OF_MEMORY or an INVALID_OPERATION error? Maybe the buffer is already mapped or something?
As far as I can understand the situation, I didn't modify anything in my VBO code.
The NullPointerException is thrown randomly (understand the JVM crashes sometimes before the Exception could have been handled).
When I get the Exception following, GL11.glGetError() returns 0 (no error)

The only way to solve this problem is by commenting (in an other class the GL11.glCallList). What I don't understand is that my code works on an other computer with the only difference being the video card (supporting oepngl 3 whereas where I get the problem it only supports opengl 1.5).
I can post a JVM crash file if needed.