The code you show looks fine. This sounds like a scope issue, meaning whatever buttons you are trying to use are not assigned any code. I don't get a good mental picture of how you have things set up, especially when you say you have two sets of buttons. If all your code is in frame 1, and you have two sets of buttons, I suspect that maybe the second set isn't getting anything assigned, though as I already said, I'm not clear on that aspect.
If you aren't getting any error messages, then it seems likely that the buttons you expect are coded are not.
SetUp is as follows:
-vivaButton, other buttons
-viva Content Movie Clip (and other respective movie clips)
The Content Clips have 2 frames:
The menu bar has a few extra frames due to the tween animation:
9: gotoAndPlay(1) (which actually stops at 1 because of the stop() tag on frame 1)
Actually, pressed the menu control button once (to swap to the second set of icons) is ok, and the second set of buttons still work, but then as soon as i return to the original set, none of them work, so i guess it is something to do with the way the menu bar is returning to the beginning?
Sorry that I'm still not clear on the workings of that menu, but if the buttons lie on different frames, then your best bet is to have the code on the frames where they are. And if you have them transition in, be sure to put instance names for each one on each keyframe.