Tween Class - Code not executed within onMotionFinished

[Vexir]

How come the code within the onMotionFinished function never executes?

import mx.transitions.Tween;
import mx.transitions.easing.*;

var topboxsectionXScale:Tween = new Tween(topboxsection_mc, "_xscale", Elastic.easeOut, 0, 100, .7, true);
var middleboxsectionXScale:Tween = new Tween(middleboxsection_mc, "_xscale", Elastic.easeOut, 0, 100, .7, true);
var bottomboxsectionXScale:Tween = new Tween(bottomboxsection_mc, "_xscale", Elastic.easeOut, 0, 100, .7, true);

bottomboxsectionXScale.onMotionFinished = function() {
	var middleboxsectionYscale:Tween = new Tween(middleboxsectiontop_mc, "_height", none, 14, 493, .7, true);
	bottomboxsection_mc._y += 479;
}

Edit:// Nevermind.