My computer has a Ati Radeon video board. and I have no problem with it. Exploring your xorg.conf you ar using a strange video adapter "fglrx" (try ati) . My sugestion is to try my configuration (in this part)
# $XdotOrg: xc/programs/Xserver/hw/xfree86/xorgconf.cpp,v 1.2 2004/04/23 19:20:02 eich ...