Drag and drop basics

Adding some basic drag and drop to a project resulted in a blank movie when I tested it. So I created a new project with just one object (ball) and applied this drag and drop Actionscript to it. Still getting a empty canvas when I test it. I'm sure I'm missing something basic, but I am not seeing it if anyone else can please. 

ball.addEventListener(MouseEvent.MOUSE_DOWN, fl_ClickToDrag);

function fl_ClickToDrag(event:MouseEvent):void
{
ball.startDrag();
}

stage.addEventListener(MouseEvent.MOUSE_UP, fl_ReleaseToDrop);

function fl_ReleaseToDrop(event:MouseEvent):void
{
ball.stopDrag();
}