When resting hands on side of trackpad, machine "freaks out"...

Can you help with a suggestion on what I can do to repair/"jimmy" my wife's MBP that, when she rests her hands to the left and right of the track pad, the machine seems to have a mind of its own. It's almost like there is a short with something right along the front edge. When I use it, I normally don't rest my hands, and lean the laptop in a different direction and it doesn't do it for me, but for her, it is nearly un-usable. I think I'm going to take it apart and have a look, but I don't know what to have a look for!!

When I press with light to moderate pressure, the cursor will jump, or a web site will page forward or back, or go to a favorite not even chosen that day.

Weird....

Any help avoiding buying a new one would be greatly appreciated. Otherwise, the machine's a champ!

Thanks

Tim