Maybe the /etc/X11 is not writable for some reason. Open up a terminal and do "ls -ld /etc/X11". It should be writable by root, like this:
Code:
su
ls -ld /etc/X11
drwxr-xr-x 17 root root 4096 Jul 16 17:54 /etc/X11
If the "w" is missing, do "chmod u+w /etc/X11".
Also check the files inside that directory,
Code:
ls -l /etc/X11
-rw-r--r-- 1 root root 3185 Jul 16 17:54 XF86Config
-rw-r--r-- 1 root root 3162 Jul 16 17:53 XF86Config.backup