ActionScript 3.0 :: Cursor Does Not Change To The Little Hand?

I've come to a really strange bug in Flash: There is a swf called Nav.swf which contains on its stage a movieclip "som" which has its own class Som.as.There's an animation on Nav.swf, and when it ends it will call the method StartPlayer() on Som.as.If I run setupButtons() in the init() function, it works fine, I am able to click the button "btPlayPause" and it will trace what's in the function clickPlayPause();

THE PROBLEM: If I leave it as it is on the example below (the setupButtons() function is only called by the startPlayer() method, which is called from Nav.swf a while later after Som is instantiated) it will trace what's in both functions startPlayer() and setupButtons() BUT the button "btPlayPause" won't work! It dosn't get the buttonMode property set to true (cursor does not change to the little hand) and when I click on it it does not run clickPlayPause(), it doesn't trace anything!

The same happens if I call directly the setupButtons() function from the nav.swf. It will trace what's in setupButtons() but the movieclip won't listen to the MouseEvent.I cleaned up the code only to show what matters:

Code:
package br.com.dialetto.nav
{
import flash.display.*;[code]..........