I am guessing you are using an ATI card? Unfortunately ATI Linux driver has always been flakey at best at 3D support (and I'm guessing the screensavers that don't work are the OpenGL ones), for quite a few years now. NVIDIA drivers, on the other hand, have always worked perfectly, with similar performance as Windows driver. That's why I have been exclusively NVIDIA since the GeForce 2 days.
Yes. It locks up on the preview when trying to select a new screen saver. I googled the problem and found others who had the same. I couldn't get past the problem without renaming the ss exe file so that the selection GUI couldn't run it. "Lattice" was the latest one giving me fits. There were others, but I haven't gone back to find all of them because I don't feel like restarting time and again :-)