connecting To PostgreSQL - Getting Error

[Riyaz@xxxxxxxxxxx]

Hello All,
    I am running Postgresql on a linux Qube and trying to connect to it using PHP. But it is giving me the following error:

Warning: Unable to connect to PostgreSQL server: connectDB() -- connect() failed: Connection refused Is the postmaster running (with -i) at 'localhost' and accepting connections on TCP/IP port '5583'? in /home/groups/smarttools/web/testpg2.php on line 21

I don't think I am using Unix sockets as I can connect to the database on psql monitor without -i option and without specifying the port number. 

Any tips on solving this?

Also in what files are connectDB - - connect() functions stored?

Thanks,
Riyaz.