If you know the correct kernel header files are installed, you may specify the kernel include path with the '--kernel-include-path' commandline option.
-> Kernel module load error: ./usr/src/nv/nvidia.o: kernel-module version
./usr/src/nv/nvidia.o was compiled for kernel version 2.4.20-4GB
while this kernel is version 2.4.20-4GB-athlon.
if you have the origional redhat disks, then you should be able to find the 'kernel-source-athlon' rpm, or something like that, somewhere. Install this, and then your problems should go away. hopefully. maybe.