Script crashes IDE and Flash Player but works in browsers

[activa]

I'm building a game program and I've got a script that loads an external swf, and then duplicates the clip for the user to play. It worked until a few days ago when I reinstalled my OS (Mac OS 10.4.11) to fix an unrelated problem. The strange thing is that I had reinstalled the browser plugin to fix a related problem. Now the code works in the browser, but crashes the IDE and the Flash Player every time. I called Adobe Support but they were no help since it's "project related." I've reinstalled CS3 and Flash itself, but nothing helps.

Here's the code that crashes:

// INITIALIZE LOADER AND ADD TO STAGE
var myLoader:Loader = new Loader;
addChild (myLoader);
myLoader.contentLoaderInfo.addEventListener (Event.COMPLETE, isLoaded);
// DUPLICATE CLIP WHEN LOADED 
function isLoaded (event:Event):void {
	event.target.content.width = 100;
	event.target.content.height= 200;
	// THIS IS THE LINE THAT CRASHES
	var copyClass:Class = Object(event.target.content).constructor;
	var newThing:DisplayObject = new (copyClass);
	addChild (newThing);
	newThing.x +=50;
}
myLoader.load (new URLRequest('coloring/coloring1.swf'));