IANA has this: fcp-addr-srvr1 5500/tcp fcp-addr-srvr1 which doesn't seem very likely. You need to look at what else is running on that machine, I'm afraid. Are you *sure* that there isn't already a listening viewer running on it? Does port 5500 appear as LISTENING in the output of "netstat -an". Cheers, Wez @ RealVNC Ltd.