Screen Saver won't auto start, with any choice - priority set to high.
kscreensaverrc has timeout=60, priority=0 (should there be a start time value?)
Have tried several screensavers with same result.
Tested at start after 1 minute - screen blinks quickly only.
Can this be changed in a file? If so, please explain.

Can you reproduce this under a new user?
Which screensaver are you trying to use?
Finally, is there any indication of why it is failing to run in ~/.xsession-errors or in dmesg?