fileReference.download

when i click. the save window opens but the image is not saved, what am I doing wrong? i have uploaded it to a test server by the way and it still doesnt work…

var myImgURL:String = 'http://www.mysite.com/images/image1.jpg';
fileDwnld.addEventListener(MouseEvent.CLICK, function down (evt:Event) {                
                    var fileReference:FileReference = new FileReference( );
                    var urlRequest:URLRequest = new URLRequest(imgURL);
                    fileReference.download(urlRequest);
                });