You might try "Detect and Repair" from either the Help menu or Control
Panel.
I just tried it on my FP2003 running on an upgraded XP ---> Vista system
and, although I hardly ever use those buttons it still works just fine for
me. The only reason I say this is because I just wanted to see if any large
software manufacturers are deliberately breaking older features of older
programs so that they won't run under Vista (like Intuit recently did to
QuickBooks 2005 for example - they broke it so you're forced to upgrade).
But, I'm happy to say that for now FP2003's Interactive Buttons are working
fine under standard operating procedures.
Try Detect and Repair from Your Help Menu or, re-install??