can't get glProgramParameteriEXT in CUDA driver?

I’m using windows XP, CUDA driver and GLLoader
I’m not 100% sure this problem is cuda-related, but i haven’t had time yet to experiment with other driver versions.

i tried to use geometry shader with a cuda program, but strangely.
wglGetProcAddress(“glProgramParameteriEXT”) always returns null
i made sure my spelling is correct (i copied the string from my program, pasted into find dialog boxes, and indeed found it in g80specs.pdf and nvoglnt.dll)

wglGetProcAddress works for other g80 extension functions like “glEndTransformFeedbackNV”,
it also works for “glProgramParameters4dvNV” and “glProgramParameter4fvNV” (glProgramParameteriEXT’s alphabetical neighborhood in nvoglnt.dll)

i noticed some posts regarding comparison between cuda list compaction and geometry shader. has anyone there experienced similar problems?