Comment 6 for bug 200665

Teoh Han Hui (teohhanhui) wrote :

gnome-screensaver should be autostarted as it is used as the default screensaver in Xubuntu 8.04. xflock4 fails as no screensaver is started and xlock is not installed.

There is an entry in the/etc/xdg/xfce4/xinitrc for loading either xscreensaver or gnome-screensaver. However, for some reason the file is not processed?