No access to MX:SWFLoader "content" after dynamic loading a SWF file

I have in my Flex app (Apache SDK 4.12.1):
<mx:SWFLoader id="loader1" creationComplete="swfLoaded(event)" complete="contentLoaded(event)"/>

I use the code below to find the SWF file: (this seems to work for both the desktop and on my Android device)
var theFile_ApplicationStorageDirectory:File = File.applicationStorageDirectory.resolvePath("/swfs/welcome_16_9.swf");
var thePath:* = theFile_ApplicationStorageDirectory.nativePath;
loader1.load(thePath);

this works fine now after hours of research but the problem is that I can't get access to "loader1.content", it is always null.
I need it so I can do an addEventListener:
loader1.content.addEventListener("MessageFromFlash", doSomething);

I get the "swfLoaded" event but not the "contentLoaded" event.

Any clues on why the loader1.content is NULL?

Jerry