"I have the same problem. Some run to the top left corner and others stand around while the ball bounces around. If I add the maximum number of ponies a really long error pops up that basically says DP has to close.
I also can't add a background, solid color or custom, to the screensaver because I get another error saying transparent backgrounds are not allowed. Which is odd because I want to add a background and the transparent background option works."
(This 100 char minimum, arg!)
I'm running Windows Vista SP2 by the way.