Ya know, I had the same inexplicable problem once and after tons of screwing around figured out that
/lib/modules/2.6.23.xxxx/modules.alias
had been incorrectly modified somehow. Some memory register 'er something was different than it was before I ran the NVidia setup program. I changed it back (since I had backups!) and it worked fine after that. Scary error though. That error message had me downloading gcc and kernels and all kindsa bananas.
