Get the nVidia 45.23 drivers here:
http://www.nvidia.com/object/winxp-2k_45.23.html
Remove your current drivers & install these instead.
Then make sure you have the file called rendogl.dll in your gpl folder
(the OpenGL patch), and give it a go.
If you still have the same problem (can't find opengl.dll) I only have
one other suggestion. Back in the 3DFX days it was fairly common to copy
one of the dlls from the system folder to the game folder & rename it to
opengl.dll.
You're right that it should be using opengl32/dll instead, but I don't
know whether copying & renaming it would work, or whether you need to do
it with nvoglnt.dll instead. Give it a go, and remember to copy, not
move ;-)
Malc.