Shut down initiated when screen saver is cancelled

[DavidM]

This is a strange problem that I have with Slickr.
If left with the screen saver runner for many hours, the PC attempts
to shut down when woken up. I'm running Windows XP Pro, and an ATI
9800 Pro with ATI drivers.
It happens if woken up by mouse or space bar, any applications are
closed one by one and the shut down window appears. No other screen
savers cause the same problem.

Any ideas what might be causing it? There are not mentions of the same
problem from other user.
David