I finally found my own solution (in case anybody else has this problem).

Attempting to configure the mouse or updating the mouse driver from the
control panel won't help. I had to go to the Microsoft site and look for
driver updates. By selecting the specific type of mouse, I could find a
newer driver (dated 6/2008) which updated the older driver dated 2004. This
has to be downloaded and installed manually. The new driver fixed the
problem instantly and hassle free.

JB

"James" wrote:

I'm using Windows XP with an IntelliMouse 2.0 and just upgraded to Office
2007. My scrolling wheel will no longer pan left and right (when tilted left
or right) in Office applications (Word and Excel specifically). I've
confirmed it still works in Adobe, photo editors and Explorer. So the
problem appears to be limited to Office apps. How can I re-enable this great
feature?