What are you calling the scroll bar? The top one above the sequence or the right side one (tracks).
Doubt its a PPRO issue because I have a lot of scroll wheel functionality.
Check the mouse drivers, Try a different mouse, check if the mouse functions are set properly in their control panel....
I had problems with using the mouse wheel to jog / frame step through media in the source
and program monitors with a logitech mouse that functioned fine with PPro2 and CS4.
After swapping to a MS mouse, the problem stopped.
Thank you for the helpful suggestions. I do believe the problem lies within the mouse driver rather than Premiere. Oddly enough, it's a Microsoft Intellimouse with an up-to-date driver and I really like it, so I'd had to scrap it for another one.
Going way back, there were several InteliPoint drivers, that caused all sorts of issues with Adobe products. After a bit, things got better, and MS seemed to be on a roll. Then, about 18 mos.back, several InteliPoint drivers went bad, regarding Adobe. Have not heard of this since, but it happened twice in the past.