ActionScript 3.0 :: Loader Class - Two SWF Files (One Loading Another)

I'm working with Loader class in as3 and there comes some really strange problem. I have two swf files, one loading the other. In the first one, I have codes like this:

var loader:Loader=new Loader();
var context:LoaderContext=new LoaderContext();
context.applicationDomain=ApplicationDomain.curren tDomain;
var req:URLRequest=new URLRequest("Untitled-1.swf");
loader.load(req);
loader.contentLoaderInfo.addEventListener(Event.CO MPLETE,onCPL);
function onCPL(e):void{
trace("finish");
addChild(e.currentTarget.content);
}

And the second one, with the name "Untitled-1.swf", doesn't seem to work in the first one. I find out that as long as there are ANY codes in the second swf file, the first one will repeat tracing "finish" endlessly.