You should listen for COMPLETE
event and set the data format to BINARY
:
var my_url1:URLRequest = new URLRequest("SWF/Lesson1.swf");
var urlloader:URLLoader = new URLLoader(my_url1);
urlloader.dataFormat = URLLoaderDataFormat.BINARY;
urlloader.addEventListener(Event.COMPLETE, function(event:Event):void
{
var myByteArray:ByteArray = URLLoader(event.target).data as ByteArray;
trace(myByteArray.length);
});