running on mine not on my friends

I am coding a game which uses volumetric fog with vertex arrays it is running on my computer.I have a gforce2 mx 400 64 mg.But my friend cant run it with a gforce mx 100 32 mg we have installed the same xp drivers from nvidias site.Any one know why this might happen??He gets the error “your current settings doesnot support volumetric fog with vertex arrays.”
THat means on his computer the game cant get the extensions… O_o