You are denied access to this VolanoChat server because someone is already connected to the server from your IP address, and this VolanoChat server has been configured not to allow duplicate addresses.
Make only one connection to the VolanoChat server using the VolanoChat, MyVolanoChat, or WebVolanoChat applets. If you received this error after connecting only once, make sure there is not someone else on your local area network already connected to the same VolanoChat server through your router.