I had the same problem a while back, if I remember right there was a directory that had 700 perms, i had to recursively change the perms to 755, I can't remember what directory it was, it may have been /usr/X11R6/gdm starts, if I log in as root, kde starts & run fine. if I log in as anyother user x fails with various messages /etc/X11/xsession : line 7 xrdb: command not found
david