Nested button inside MovieClips

I am sure I must be doing something very stupid but here goes:

This is for a navigation bar.

  • I have a main movie (mcMenu) on my stage which holds all the main buttons (btnHome, btnAbout, etc…).
  • Inside mcMenu, when I roll over say btnAbout, the movie plays from 10 to 20th frames during which time a submenu fades into view.
  • Inside this submenu, I have the sub-section buttons. It is these buttons that I am having problems with. Basically, I can’t get them to respond to onRelease events.

What could I be doing wrong?

Thanks.