Your monitor setup slightly confuses me.. could you describe what the intention is?
Is the kernel module 'nvidia' loading cleanly? Try loading it manually to be sure, prior to attempting the X start. If you need to, boot to runlevel 3 first, then load the module, and switch to runlevel 5.
then telinit 5
It looks to me like the kernel module may be the issue, but if not then perhaps start looking at libraries.
posted describes where the libraries are installed, and how they should be linked to each other. Verify that the libraries in /usr/lib/*GL* are linking as they should.. and not picking up libraries from the XFree86-Mesa-libGL package. On RH9 I regularly just removed that package to avoid conflict. Alternatively, you might try installing using rpm packages from atrpms which relocate the nvidia libs to avoid conflict: http://atrpms.net/dist/rh9/nvidia-graphics/
(to switch to the rpms, you should uninstall the nvidia driver, reinstall / freshen the XFree86-Mesa-libGL package if you have it installed, then install the rpms)