Visible = false?

Okay, normally i got Claudio on my msn to bug with these kinda questions, but hes not online.

My problem is, that i have this sorta drop down menu, which should be closing when i roll over a big mother ****er area in the background. This code on the background:

on(rollOver){_root.antenne_menu.visible = false;}

This on the button that should show the menu:

on(rollOver){_root.antenne_menu.visible = true;}

and this on the first frame of the timeline:

_root.antenne_menu.visible = false;}

Now the problem is, that nothing works. I could use _alpha of course, but i can still press the submenus, they has just gotten invisibles. So help me if you please