I hate to say but I deinstalled the program.
It worked nice, made my own login screen, loved it, but I figured out, that the program blocked the screensaver. After the deinstallation the screensaver worked again (W2000SP4)
Somewhere was an info about problems with screensavers and a login as normal user AFTER a login as admin.
So, perhaps it is important, that I am not working as an admin but as a normal user, btw: the login as an admin didn't solve the problem :-(