Connect to the console of the server using SSH and run the following command:
psql -h localhost -U postgres -c "UPDATE tbl_parameters SET value = 'false' WHERE name = 'login_initialized';" global_data
This will allow you to reset the administrator password on the next login.
When installing on a Windows server, Faddom uses integrated Windows authentication and gives administrative access to the user that performed the initial installation. If you have lost access to the user that installed the software you should reset the password for that user through Active Directory.