"Connection refused"

Hi,

I am very new to PostgreSQL's jdbc. After following the installation and configure instructure of
http://www.fankhausers.com/postgresql/jdbc/, I get an error message "***Exception: Connection refuled. Check that
the hotname and port is correct, and that the postmaster is running with the -i flag, which enables TCP/IP networking"
when I run the test program. What I am missed here?

Thanks in advance.

v.