Some people are having issues running this java demo under netscape so use IE if you can. Known working configurations - PC running 95, 98, 98SE and 2000 (& ME Althought it runs slow). Browser used IE 5+. For running the "indy.jar" executable contained in the downloadable copy directly you must have a java runtime installed compatible with your system more details below.
Remember this is just a throw around demo, there is a Troubleshooting Guide here if your still having problems.
If your on a slower connection (56k) you might want to download A Zipped Copy here and click on indy.htm to run. As some people with such connections are complaining that their browsers are hanging. A version history can be found here.
If you STILL cant run it then try and update your browser or get a new version of the JDK from Sun Java (look under products and APIs).
NOTE FOR MAC USERS! You can snatch an macintosh runtime here if you want to run the indy.jar file directly through the downloaded copy.
Anything else you can Mail me.