hm.. "unable to determine kernel version", that sounds odd..I would have thought that the installer only checks out whether it's 2.4 or what and then do the job if the version corresponds to the driver's target?
did you download the 4496-version of the driver from nvidia's site? and another thing: when running the .run -file, I recall it should verify the .run file (itself) so that it isn't corrupted...do you see this type of message? in terminal, the first line after doing a ./NVIDIA-Linux-x86-1.0-4496-pkg1.run (or whatever the name is), should be
Verifying archive integrity... OK
do you get this message? if not, then obtain an uncorrupted file..but if you do get this, then it can't be the driver.
so did you recompile your kernel? (after starting the config, they should be in Device Drivers -> Graphics Support) I'd suggest that if you have downloaded the sources, do a "make menuconfig" and see the list of "supported drivers" I mentioned above. if there is the name of your card, add it (as module or built in) and recompile...if there isn't. then it's of course no use to recompile I guess, but if there happens to be, it just might help.
for instance, if your card would be the "bad old" riva TNT, you would recompile the kernel with "nVidia Riva support"...if nothing else seems to help, try checking if your card is in the list
mine didn't work before I enabled one of those as a module in my kernel.