I have my Stage. On this I have an empty MovieClip (MC).
To begin with I do:

MCContent = new TestMC();

This works.

But in my TestMC, I have another MovieClip Button01, which is named Button01, where I have the code:

Button01.addEventListener(MouseEvent.MOUSE_UP, handleMouseUp);
function handleMouseUp(event:MouseEvent):void {
trace('Hello World);

But when I click on Button01 nothing happens... What am I doing wrong?