Had an issue where the FIM Portal was being installed on a separate server than the FIM Service.
Receiving an error message during the FIM Portal installation:
"The FIM server you have entered does not exist or is not running. Click 'Back' to enter a different server name. If you plan to install the FIM service on '<server name>' later, click 'Next' to accept the configuration and continue."
Found there was a network firewall between the FIM Service Server and the FIM Portal box.
Steps for Resolution
http://<FQDN of FIM Service Server>:5725