AIR 3.9 for android, how to load file in primordial worker

when i use AIR 3.9 for android version of my game, i can not load file in primordial worker swf.

I use the code below:

var loader : URLLoader = new URLLoader();

loader.dataFormat = URLLoaderDataFormat.BINARY;

loader.addEventListener(IOErrorEvent.IO_ERROR,

     function (evt : IOErrorEvent) : void

     {

          trace("load file error: " + evt);

     }

);

loader.addEventListener(Event.COMPLETE,

     function (evt : Event) : void

     {

          trace("load file completed: " + evt);

     }

);

loader.load(new URLRequest("./music/bgm/bgm_title.mp3"));

and already set the second parameter of "WorkerDomain.current.createWorker(swf:ByteArray, giveAppPrivileges:Boolean = false):Worker" giveAppPrivileges to be true.

this code can work on desktop AIR, but failed in android AIR, it tells a IOErrorEvent, and report "Stream Error".

So, is it a bug of AIR 3.9 for android, or is there somthing i missed?

Thank you very much for any help.