Please close the bugreport, the option "DPMS" was not in the xorg.conf. I think the proble occoured during the change from xfree86 to xorg. I am not beginner level in linux but never heard from this setting. I think the kdecontrols screensaver could add some warning or an solution when the user is configuring screensaver and this is not setted in the xorg.conf. It confused me very much that xscreensaver was working...