one giant media

If you seem to have everything set up correctly with a Loader class instance, but there's just nothing happening... You probably made the same mistake I've made a number of times when coding a little too quickly:  attaching the event listeners to the Loader object itself, rather than your loader's property: .contentLoaderInfo - where all the information and events on loading status actually occur.

For example...

 The Common Wrong Way:

var myLoader:Loader = new Loader();
myLoader.addEventListener(Event.COMPLETE, onLoadComplete);
myLoader.load( new URLRequest("externalExampleImage.jpg") );

...and then you wonder why the event never fires, there is no error, and you know your image is there... doht!

The Right Way:

var myLoader:Loader = new Loader();
myLoader.contentLoaderInfo.addEventListener(Event.COMPLETE, onLoadComplete);
myLoader.load( new URLRequest("externalExampleImage.jpg") );

... works every time!

Adobe Documentation Reference:

http://livedocs.adobe.com/flash/9.0/ActionScriptLangRefV3/flash/display/LoaderInfo.html