wglCreateContext failure

I have a problem with creating my OpenGL rendering context. The call to wglCreateContext returns NULL. The string returned by GetLastError() is “DLL initialisation routine failed”. The pixelformat returned by ChoosePixelFormat is 3.
What could be the problem?
This problem does not occur with Nvidia 23.10 drivers, but crops up with 27.70, 28.32, 29.42. I have a GeForce3, Windows 2000

many thanks,