[zurkis]

my_btn.addEventListener(MouseEvent.CLICK, myBtnClicked);
 
function myBtnClicked(e:MouseEvent):void {
    var url:String = "http://ifoow.h16.ru";
    var request:URLRequest = new URLRequest(url);
    try {
        navigateToURL(request, '_self');
    } catch (e:Error) {
        trace("Error occurred!");
    }
}

попробуй так