ActionScript 3.0 :: Scroll Not Working Using UIScroller Bar?

I have a dynamic text field that has some external text loaded in with a UIScroller Bar attach. i have set the scrollTargetName using the components inspector and the text and scroll work fine when tested locally. however, the scroll bar does not work in safari or firefox. the text is loaded but the scroll bar does not work.

i read a thread elsewhere that suggested using the scroll bar update function but this didn't work.

here is my code for loading in the text.

var myTextLoader:URLLoader = new URLLoader();
myTextLoader.addEventListener(Event.COMPLETE, onLoaded);
function onLoaded(evt:Event):void {
textBox.htmlText = evt.target.data;
}
myTextLoader.load(new URLRequest("returns.txt"));