Problems with buttons and a timer

Hey Guys,
I’m new here and though new to actionscript I have some Java programming under my belt. I was looking for some help for a problem I’ve been having. I am trying to build an image slideshow which loads button thumbnails and automatically advances through the slideshow even when the user doesn’t click one of the buttons. I have a timer that counts down from 5 and then switches the main image while adjusting the alphas of the thumbnails. The way went about the thumbnails was to load them from some xml and then push them onto a thumbnail array.
Here is a piece of that function

   var container:MovieClip;
            var i:int;
            for (i=0; i < xmlList.length(); i++) {
                
                   thumbLoader = new Loader();
                   thumbLoader.load(new URLRequest(xmlList*.attribute("thumb")));
                   container = new MovieClip();
                   container.addChild(thumbLoader);
                   container.buttonMode = true;
                   thumbArray.push(container);

Now, I figured I would just jump through the array adding the button functionality. But the code to enable buttonMode only seems to work before the timer goes off. As soon as the timer goes off the button breaks. Any ideas?