I'd have said that the other thread was in the most approrite location but nevermind, this one seems to be getting the most action
Have you changed anything in your kernel? There are options that I believe are used by X when you use DRI support, you might want to have a look into your Kernel config and see if any of your settings seems strange. Have a read of the kernel howto at http://www.linuxdoc.org/HOWTO/Kernel-HOWTO.html
if you've never done a recompile before. Unfortunately I can't remember exactly where the options are and don't have a 2.4.x Linux machine available to have a look at the moment - anyone else give the correct location in the kernel config??