Problems

If it didn't work it might be that your browser does not have Java applets enabled. To enable applets in Netscape Navigator, go to Edit/Preferences/Advanced and check that applets are enabled. In Microsoft's Internet Explorer go to go to View/Internet Options/Advanced.

If you are working at a computer furnished by a company or university, or are behind a firewall, applets may have been permanently disabled. In this case there is nothing you can do.  

Old browsers do not support Java. Some browsers only support older versions of Java. If your browser is more than a few years old, get a newer one.