I had exactly the same problem. Here is how i solved it step by step
1. rpm -ivh --force fglrx***.rpm (download the rpm from
www.ati.com )
2. install your kernel sources (if you have your default kernel on mandrake 9.2 that should be 2.4.22-10mdk , if you don't have them on your distro cd's try a google search 2 download them )
3. cd /lib/modules/fglrx/build_mod
4. run make sh ( that is " ./make.sh " )
5. cd ..
6. run make_install.sh ( " ./make_install.sh" )
7. run fglrxconfig to set up your settings and make sure to say yes when it ask you if you want an agp gart module (that way you'll have 3d accelaration )
8. restart the server
9.Voila!(Hope thats spelled right!)
10. to check your 3d settings open a console and run glxgears (that should display 2 gears running ) I have a p4 2,4ghz (overcloacked @ 3.06 ghz(!!!)) 512 mb ram and ati radeon 9600 ro and i get round 4800 FPS
11. Good luck!!