EDIT: Never mind, I figured it out. Just in case anyone else stumbles upon this with the same problem, I just added the ldr.content to the display list and it worked 
sorry for resurrecting this old thread, but it was just what I was looking for in terms of using an swf's bytes. So I did this, and created a simple animation of a box moving:
PHP Code:
var cow:Cow = new Cow();//makes a box come on the screen
cow.addEventListener(Event.ENTER_FRAME,onLoop);
function onLoop(evt:Event){
cow.x++;
if(cow.x>550){
cow.x = 0;
}
}
This works great in the original file, but when I load this as a byte array, I can't figure out how to make this "play." I want it to run just like the original file. Any ideas?