Need help with Enabling disabled buttons!

So, here’s the setup:

I have a main .swf with 27 buttons on it. Once a button is clicked I use (in a seperate .as file)

btn_ButtonName.onRelease = function() {
btn_ButtonName.enabled = false;
loadMovieNum(“NewMovie.swf”, 5);
}

to open the NewMovie.swf in the 5th level. Everything works fine up till here. Now, on the NewMovie.swf file I have a close button. The scripting I have so far is

on(release) {
_root.btn_ButtonName.enabled = true;
unloadMovie(this);
}

This should work, yes? Unfortunately, it does NOT work!! Please help!!

P.S. - I have 27 buttons that I need to disable/enable, I only entered one into my examples to save space.