can you temporarily remove /usr/X11R6/lib/X11/rgb.txt, restart the xserver and post your /var/log/Xorg.0.log and your /var/log/Xorg.0.log.old ?
can you temporarily remove /usr/X11R6/ lib/X11/ rgb.txt, restart the xserver and post your /var/log/Xorg.0.log and your /var/log/ Xorg.0. log.old ?