Umm Im not runnign Mandrake but Im pretty sure you have to have the haeders intalled and stuff: linux-2.4.x-devel.rpm?
It is generally accepted that installing from the .tar.gz's works better. There is goldmine of knowledge in the linux & nvidia forum here why not try having a look. TIP: If you are having trouble installing a rpm and its complaining of dependancies that you know are satisfied try adding --nodeps as a option, and or --force for that matter.
BTW for a "noob" you did the right thing by stating what you tried to do and the error resulting from it. It helps the volunteer helpdesk guys imensly.