Either your browser does not have Java or its java is older than version 1.1. To play the Rush Hour demo, you need a browser with Java 1.1 or later. Almost any system can get a free browser that does this. Here is a chart of browsers that will work, and where to get them:

Platform Browser Where To Get It
Windows 95/98/NT Microsoft Internet Explorer version 4.0 or later
Windows 95/98/NT
Unix Systems
Netscape Navigator version 4.50 or later

If you have one of these browsers and you still get here when you try to play the Rush Hour demo, then you may have Java disabled. Look in your preferences, options, and security options and make sure that Java is not disabled. Also, some versions of Microsoft Internet explorer need to have a Java plugin from Sun before they work; the link to get this plugin is listed in the chart above.