Major Problem, need help! Can't run our website!

Anyone!

Before anything else, I have no background in PostgreSQL. But I have a
little knowledge in Linux. We used postgreSQL to run one of our website. It
runs in Redhat Linux 7.3. Our System Administrator, who used to maintain
this server, had resigned and didn't have a proper documentation on how to
maintain this server. Right now, our NEW System Administrator is clearing
some logs in /var/lib/pgsql/data/pg_xlog in able to free some space in the
/var file system. It used to work before, but now, its not working anymore.
Information below is the message we are encountering when we are trying to
connect to the website. Please, ANYONE, help us!

Warning: Unable to connect to PostgreSQL server: could not connect to
server: Connection refused Is the server running on host localhost and
accepting TCP/IP connections on port 5432? in
/var/lib/phplib-7.2d/php/db_pgsql.inc on line 48
Database error: Link-ID == false, pconnect failed
ODBC Error: 0 ()
Session halted.

Thanks! --AGUEDO