let's imagine this scenario:
A.swf loads B.swf
after load is completed,A.swf needs to execute a function in B.swf called runCommands() for example.. here is the code for that (this is the code inside A.swf):
import flash.display.Loader;
import flash.display.LoaderInfo;
import flash.events.*;
import flash.net.URLRequest;
...
var loaderRequest:URLRequest = new URLRequest("B.swf");
var movieLoader:Loader = new Loader();
movieLoader.contentLoaderInfo.addEventListener(Event.COMPLETE, completeHandler);
movieLoader.load(loaderRequest)....
function completeHandler(_event:Event)
{
var _loaderInfo:LoaderInfo = _event.target as LoaderInfo;
var loadedObject:Object = _loaderInfo.content;
loadedObject.runCommands()
}