When the software says that it needs a server, it means that you actually downloaded a client that connects to a backend software where the database is hosted and where the rooms are stored. I also don't think you will be able to ever user the software anymore primarily because the official website is not working anymore. It's available only through the Archive.ORG website, a portion of the Internet where the certain websites are still indexed.
Currently, the ICUII isn't operable due to the fact that you are lacking a server and since the official website is not available anymore.