ActionScript 3 - Flash saves file on Windows, not Linux: FileReference.save()

/*
    WriteTheFile.as
    Original code by Brian Hodge (brian@hodgedev.com)
    Test to see if ActionScript/Flash can write files
    */
    package{
    import flash.display.Sprite;
    import flash.events.Event;
    import flash.events.MouseEvent;
    import flash.utils.ByteArray;
    import flash.net.FileReference;

	public class WriteTheFile extends Sprite 
	{
		private var _xml:String;

		public function WriteTheFile():void 
		{
				if (stage) init();
				else addEventListener(Event.ADDED_TO_STAGE, init);
		}

		private function init(e:Event = null):void 
		{
				removeEventListener(Event.ADDED_TO_STAGE, init);
				//Calling the save method requires user interaction and Flash Player 10
				stage.addEventListener(MouseEvent.MOUSE_DOWN, _onMouseDown);
		}
		private function _onMouseDown(e:MouseEvent):void
		{
				var fr:FileReference = new FileReference();
				fr.save("<xml><test>data</test></xml>", "filename.txt");
		}
	}
    }