screensaver stops working

Hi List, This is a P-III 950 MHz, 640 MB RAM system running SuSE 8.2 stock and patchd with the latest upgrade packages. I run 16 desktops on kde with all of them having at least one or two application windows open, vmware and a win98 guest being one of them. Occasionally I experience the lack of screensaver action. For no apparent reason the screensaver stops kicking in after its prescribed 5 minutes. When I restart kde everything is fine ... for a couple of days until the problem reappears. Has anybody else seen this behavior? Where should I start to probe and trouble shoot? Thanks for any pointers, ALex.