Stuck on chat? Try these suggestions one by one :

If you have Internet Explorer and Netscape Navigator, then give both a try.

If you go into Control Panel > Add and Remove Programs, have a look for a program called Java Runtime 2 (or something similar), try uninstalling it.

If neither of the above work, go to the Java website and install the plug-in, dead easy, just go for a Manual Download and Save the file to your desktop.

There is also a thread on the messageboards which can be accessed here.