I can also confirm this issue, after some time either a blank screen or a large screen filling or small x appears. I have worked around the issue by enabling power management and setting it to the maximum setting of five hours in the control panel.
I'm running Kubuntu 6.10, it is a fresh installation. -- Disabling energy saving of monitor; changes the normal screensaver to a e.g. blank screen or a screen with an X https://launchpad.net/bugs/70991 -- kubuntu-bugs mailing list kubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/kubuntu-bugs
