Opensuse crashes on inactivity?

Good evening;
it is the second time it happens.

When i leave my computer for a moment i can see the screensaver completely frozen, nothing responds: keyboard, touchpad… I can preview the screensaver correctly, one with an ASCII aquarium.

What can be causing this?

Opensuse 11.3, 2GB Swap, fresh install

I could sucessfully freeze my PC again in the screensaver select dialog, by previewing several ones.

(P. S. Sorry for the double post, but i searched for an edit button with no luck.)