LocaltoGlobal/globalTo Local prob again

Hi a bit new to coding so i need help with this

here is the code on the action panel of an mc(movie clip)

onClipEvent(enterFrame) {
point = new object();
point.x = _root.movie.button._x;
globalToLocal(point);
trace(point.x );
updateAfterEvent();
}
the value of point.x is 0.5 before the globalToLocal and i am trying to get its value in relation to this mc but even after the globalToLocal the value traced is still 0.5
I would really appreciate some help
Thanks