Código PHP:
var direccion:URLRequest=new URLRequest("leter.swf");
var loader:Loader = new Loader();
botoncito_btn.addEventListener(MouseEvent.MOUSE_DOWN, carga);
function carga(event:MouseEvent):void {
while (this.numChildren) {
this.getChildAt(0).parent.removeChild(this.getChildAt(0));
}
loader.load(direccion);
this.addChild(loader);
}