had that problem too when my radeon 8500 was state of the art.
X does not seem to recognize your videocard (at least that was my problem when I had your problem)
now what is your xfree version?
which videocard do you have?
X -configure, use that config file (edit some small stuff later). (make sure you use the latest xfree (4.3, in 2004 4.4))
And Wow, there are other belgians using Linux.