Leopard & Wireless Mighty Mouse

My friend and I have nearly identical MBP's which for we bought the group Leopard and installed onto them...

My Wireless Mighty Mouse works perfectly... her's, well, not even close!
It spazzes out all over the place! She uninstalled and reinstalled... but the same thing is happening.

Has anyone else had this problem or does anyone know a solution?
Thanks.

I have to admit that my mouse has been acting a little weird since I installed Leopard. The cursor will periodically and randomly jump across the screen. It doesn't happen all that often, but it is becoming a bit of an annoyance. Any ideas on what's causing this?

Sean