unloading an external swf from itself

There are a couple ways you can do it, including using parent to simply call a function in the main timeline. I'd probably use an event though - have your main swf, the one doing the loading, listen for a custom remove event on the loaded swf's and removeChild on them. So, in your return buttons you coud do:

function returnClicked(e:MouseEvent = null):void

{

     parent.parent.removeCurrentSwf();

     dispatchEvent(new event("removeLoadedContent"));
}

So, either line 1 or 2... not both.

Line 1 is a bit more fragile, if you change your content around it could stop working because it relies on the hierarchy. The event method is better - you just then also have to add the listener when you load in your movies:

var myLoader:Loader = new Loader();
myLoader.load(new URLRequest("b2.swf"));
myLoader.contentLoaderInfo.addEventListener(Event.COMPLETE, addRemoveListener, false, 0, true);
addChild(myLoader);

function addRemoveListener(e:Event):void
{

     myLoader.contentLoaderInfo.removeEventListener(Event.COMPLETE, addRemoveListener);
    e.target.content.addEventListener("removeLoadedContent", removeCurrentSWF, false, 0, true);
}

function removeCurrentSWF(e:Event):void
{
    trace("got it");
}