Got it sorted, all is OK.

Hi, VERNCon

If you found a trick, please share with the community, it could help someone.
Thanks in advance.

Hi,
It was much simpler than I expected....
In the parameters.php file, at $paramDbHost value, all I needed to do was enter the Unix Sockets directory for the connection.
In my case (Fedora with PGSQL), I entered "/var/run/postgresql/" and re-started the httpd Service.

You need to have the database listening on the appropriate Unix Sockets - the default for PGSQL is /var/run/postgresql/ and /tmp.

The code used in this software is obviously much "nicer" than others, as I did the "usual" and I replaced the / 's with %2f, but then it complained that it could not parse the value.
I tried the straight text string including the forward-slash, it happily accepted it and the database connection came straight up. You still need to correctly edit the pg_hba.conf file correctly to control the access.

Cheers,
Verncon.