Simple PrintJob question

programming flash
1

I’m having some trouble getting a Sprite to print. I’ve made a test file just to see if I can get a basic print job to work:

 
printBtn.buttonMode = true;
printBtn.addEventListener(MouseEvent.MOUSE_UP, printReport);
var testSprite:Sprite = new Sprite;
addChild(testSprite);
 
function printReport(e:MouseEvent):void {
 var pj:PrintJob = new PrintJob();
 pj.start(); 
 pj.addPage(testSprite);
 pj.send();
}

It seems to me that’s about as simple as you can get.

I get the following error no matter what I do:

Error #2057: The page could not be added to the print job.

Obviously I am overlooking something here.