Can anybody help me with this?

I'm trying to insert a external SWF file into an existing fla. presentation, I can insert the swf, but when I try to change location I can't change it.. and also after the external swf loses the interaction it has!

import flash.display.*;

import flash.net.URLRequest;

var rect:Shape = new Shape();

rect.graphics.beginFill(0xFFFFFF);

rect.graphics.drawRect(0, 0, 100, 100);

rect.graphics.endFill();

addChild(rect);

var ldr:Loader = new Loader();

ldr.mask = rect;

var url:String = "360ProductViewerFX.swf";

var urlReq:URLRequest = new URLRequest(url);

ldr.load(urlReq);

addChild(ldr);

thanks in advance!