[Resolvido] Lista de exibição - DisplayObject

Tenho 3 movie clips: largeContainer, smallContainer e child (instâncias: child0, child1, child2)

largeContainer recebe smallContainer, child0 e child1

smallContainer recebe child2

child recebe texto

//import flash.display.MovieClip;
//import flash.display.DisplayObject;
//import flash.display.DisplayObjectContainer;

function showChildren(dispObj:DisplayObject):void {
for (var i:uint = 0; i < dispObj.numChildren; i++) {
	var obj:DisplayObject = dispObj.getChildAt(i)
	if (obj is DisplayObjectContainer) {
 trace(obj.name, obj);
 showChildren(obj);
	} else {
 trace(obj);
	}
}
}

showChildren(stage);

Deve exibir em output:

root1 [object MainTimeline]
largeContainer [object MovieClip]
[object Shape]
smallContainer [object MovieClip]
[object Shape]
child2 [object MovieClip]
[object Shape]
[object StaticText]
child0 [object MovieClip]
[object Shape]
[object StaticText]
child1 [object MovieClip]
[object Shape]
[object StaticText]

Estou refazendo o exercício de um livro, observei a mesma ordem para os mcs, mas obtenho erro em 2 linhas do code:

Line 4 1119: Access of possibly undefined property numChildren through a reference with static type flash.Display:DisplayObject

Line 5 1061: Call to possibly undefined property getChildAt through a reference with static type flash.Display:DisplayObject

Arquivo original + exercício com erro - salvei na versão CS4 >> http://rapidshare.com/files/442092804/DisplayObject.rar

Agradeço quem puder dar uma luz.

Abraços