Zoom с помощью transitions

[DrugON]

function loaderCompleteHandler(evt:Event):void {
	var vars:URLVariables = new URLVariables();
	vars.decode(evt.currentTarget.data);
	pictures = new Array();
	transitions = new Array();
	for (var i:int = 0; i < vars.Totalnumber_of_entries; i++) {
		try {
			var picture:Picture = new Picture(vars["foto_url" + i]);
			addChild(picture);
			pictures.push(picture);
			picture.posX = 100;
			picture.posY = 100;
			picture.addEventListener(MouseEvent.MOUSE_OVER, mouseOverBox);
		} catch (err:Error) {
			trace("BAD");
		}
	}
}
 
function mouseOverBox(evt:Event):void {
	var selectedBox:MovieClip = MovieClip(evt.target);
	selectedBox.removeEventListener(MouseEvent.MOUSE_OVER, mouseOverBox);
	var myTransitionManager:TransitionManager = new TransitionManager(selectedBox);
	myTransitionManager.startTransition({type:Zoom, direction:Transition.IN, duration:1, easing:Regular.easeOut, shape:Iris.CIRCLE});
	transitions.push(myTransitionManager);
	myTransitionManager.addEventListener("allTransitionsInDone", animationComplete);
}
 
function animationComplete(evt:Event):void {
	evt.target.content.addEventListener(MouseEvent.MOUSE_OVER, mouseOverBox);
}

Не получается сделать zoom для картинок. При наведении на картинки пишет ошибку

TypeError: Error #1034: Type Coercion failed: cannot convert Picture@10e2cd29 to flash.display.MovieClip.
	at index_fla::MainTimeline/mouseOverBox()

Помогите разобраться.