The one problem with Ajax-enabled applications is that it is difficult to know what is going behind the scenes. It is even more difficult to know what happened when something goes wrong. Your activity indicator image keeps spinning, but the nothing seems to happen on the page. FireBug will help you figure exactly what went wrong and where.
You need Firefox 1.5 to use FireBug. Even if your primary browser isn't Firefox, it is worthwhile to have Firefox with the FireBug inspector installed on your machine just for the purpose of debugging. Installation is very simple. Simply go to http://www.joehewitt.com/software/firebug and click the large "Install FireBug" button and follow the directions. After installation you'll need to restart Firefox for the extension to complete installation.
After reopening your browser, you can change FireBug's visibility by using Firefox's view menu bar at the top of the screen, or by ...