OK, do this:
change DISPLAYMANAGER_XSERVER="Xgl" to DISPLAYMANAGER_XSERVER="Xorg"
go to ~/.kde/Autostart
If you followed posted howtos, you probably have a "startcompiz.sh" script in there or in /opt/kde3/share/autostart with the following contents:
Exec=compiz --replace decoration wobbly fade minimize cube rotate zoom scale move resize place switcher & gnome-window-decorator &
THis file should be either removed, or moved to a location where KDE will not load it.
THis last part is the actual cause of the problem, but it indicates that you might have some of the other items still configured. What that file does is instruct KDE to run compiz, to remove the window decorations and replace them with compiz's window decorations. Of course, since you disabled xgl via the gnome control panel, xgl is not enabled, and compiz, which depends on xgl, crashes in the process, leaving you with no way to manage the windows.