Problems with AssertOpenGL

1
I downloaded PTB-3.0.8 onto a Windows XP machine running Matlab 7.4
with an NVIDIA geforce4 4200 Go graphics card. When the post-
installation routines attempt to run I receive the following error:
??? Error using ==> AssertOpenGL at 54
This script or function is designated to run only an Psychtoolbox based
on OpenGL. See AssertOpenGL.

Error in ==> PsychtoolboxRegistration at 59
AssertOpenGL;

Error in ==> PsychtoolboxPostInstallRoutine at 93
PsychtoolboxRegistration(isUpdate, flavor);

Error in ==> UpdatePsychtoolbox at 157
PsychtoolboxPostInstallRoutine(1);

Any ideas?

Thanks,
Ian