Software :: Screensavers Cancelling On Macbook?

Just bought a new Macbook and everything's great except the screensaver facility. I'm primarily using the one that previews album covers from itunes, but it doesn't really matter which one I use. They all cancel themselves after a few seconds as though the trackpad's been activated, even though I'm nowhere near it.

I've obviously tried restarting to see if it makes a difference and it usually does for about an hour. The screensaver comes on and stays on. But I'll do some work and check it again later by activating a hot corner and it quits again after a few seconds like before.

This is hardly the end of the world, but it is pretty annoying. Anybody else had this happen on Snow Leopard and is there a way to fix it?