I'm not sure if anyone has come across this problem before, but it's very annoying. I've got sick of my Mighty Mouse at work and brought in my Targus Bluetooth Mouse from home, which works seamlessly and always has on my home machine.

At work however, while moving my mouse around (say, in a Photoshop or Illustrator document), the page haphazardly scrolls in the direction the mouse is moving - only horizontally though. At first I thought it was limited to the Adobe suite but it's happening in Finder too.

And no, I'm not resting my finger on the optical scroller

If it helps, my machine at work is running 10.5.8 and I have installed the latest drivers/software for the mouse.
I've been using this mouse since about 10.4 on machines at home (now running Lion) and never really had any issues.

Anyone have any clue what's going on or how to fix it?

EDIT: Post has nothing to do with Microsoft Windows. Typo in the thread title. My windows are behaving badly, not my Windows.