I went through the same thing:
1) Installed the 2007 mini. It somehow was unable to freaking contact the FTP site and download the packages I selected so I had a mostly bare install.
2) Friend helped me configure urpmi settings or what not. Downloaded KDE.
3) Was unable to startx, got the "i810 module not installed" (or whatever it is) - driver not found.
4) Friend guided me through downloading/installer FDrake. Ran that and got the other error saying the server module did not match - friend told me that the Video Chipset I thought I had probably was not it.
5) In FDrake, selected a Generic VGA X, which gave me problems (at the end it gives ya the option to "test" your settings) saying the driver could not handle the resolution I had selected (1024x768, 24 bpp - I think). Kept picking a lower one until I ended up with 640X480, 8 bpp (or some ridiculous number like that).
I was able to STARTX!
but the graphics are HUGE so, I'll have to take a closer look at the PC and see what the heck it has for Video to make sure I go back and alter it (either through the GUI or through FDrake).
In short - if you're having the same issues I described above, there is a good chance you're not selecting the right video driver. You may not be able to trust what the internet says your PC "should" have by default - and may need to actually open the darn box and see for yourself - which is what I'll be doing shortly.
Hope that helps y'all - cheers.