Have you tried using CiscoWorks in another browser (IE, Netscape, Opera)?
Do you see the same problem if so?
Most often these problems are associated with Java on the client desktop.
Try another browser.
Try uninstalling Java 1.3.1 - automatically re-install when you connect to CiscoWorks again.
Right click on the Java Console icon in the systray and select Show Console to see if any errors are coming up when launching User Tracking.
Make sure your browser settings are correct.
Good luck.