xorg-server's ABI did change that's why it doesn't match your video drivers' ABI any more.
You should recompile xf86-video-ati against your new X server.
And better install xf86-video-vesa as well just in case you would have a problem with ati.
PS You could recompile xf86-video-fbdev against your new X server as well, though I am not sure it be usable in your system.
Last edited by Didier Spaier; 06-25-2012 at 05:36 PM.