This is my case (the same):
Warning: loading /lib/modules/2.4.21-166-athlon/kernel/drivers/video/nvidia.o will taint the kernel: non-GPL license - NVIDIA
for information about tainted modules
Module nvidia loaded, with warnings
and all that Stefan says is equal for me!!! Is it possible that only 2 guys have this kind of problem?
Thanks for the support, Stefan and Whig...