I haven't had much luck with Sax2 either. It seemed to change things around in ways that the driver didn't want, like glx in your case. the key in the XF86Config file is to make sure you are using the 'nvidia' driver, not the 'nv' or 'fbdev'. Check the readme on nvidia's site to see what options exist for the driver too, if you want to change those.
as to the glx module, you have it, but it is named (for a couple reasons) in such a way it is not being found. run this command:
ln -s libglx.so.1.0.5328 /usr/X11R6/lib/modules/extensions/libglx.so
then it will find it. My preference would be to install the driver again so everything gets put back (there are some libraries that use the same link-to-where-X-wants-it method Sax2 might have changed).
Or maybe a newer version of Sax2 would help, if there is one.
- make sure driver's parts are in the right place (running the driver's install script would do this. mostly harmless
- use the 'nvidia' Driver in XF86Config, not 'fbdev'.
hope this helps