The initial issue just sounds like a crappy ScreenSavers hack (where did you get it?) or a PEBKAC, because that's the behavior of the framework when it hits a screensaver file it doesn't like: it does nothing, just goes to sleep without updating the screen.
Now, with the new device, your best bet is to jailbreak it through Kubrick, which, like ixtab just said, should work.
FYI, the K5 ScreenSavers hack lives
here.