Connecting via postgresql jdbc

I have not been able to connect to postgresql via postgresql jdbc. The problem is not with postgresql jdbc because tcpdump on the postgresql host shows that the connection is getting through.

The message I get from the java app is that the connection is refused. The username passed by DriverManager.getConnection works from psql on the postgresql host. I'm sure I know the password for this user and tried using a null string for the password too with the same result.

I'm running the java app on windows xp pro connecting to postgresql 8.3.5 on centos 4.7 via postgresql-8.3-604.jdbc4 on an private network. The hosts files are configured correctly. The postgresql.conf file has listen_addresses = '*'. Pg_hba.conf IPv4 local connections is:
host all all 192.168.1.0/24 MD5

TIA,
Bruce Hyatt