cannt setup postgresql database for my opennms

I am using linux Red Hat 8 OS, it may be 2 old now, ^_^
I have just installed my opennms by rpm package, and now i am running
the installer to setup the PostgreSQL database:
# $OPENNMS_HOME/bin/install -disU
but some exception happens:
==============================================================================
OpenNMS Installer Version $Id: Installer.java 3056 2006-03-26 19:39:16Z
djgregor $
==============================================================================

Configures PostgreSQL tables, users, and other miscellaneous settings.

Exception in thread "main" org.postgresql.util.PSQLException:
Connection refused. Check that the hostname and port are correct and
that the postmaster is accepting TCP/IP connections.
at
org.postgresql.jdbc1.AbstractJdbc1Connection.openConnection(AbstractJdbc1Connection.java:204)
at org.postgresql.Driver.connect(Driver.java:139)
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at
org.opennms.install.Installer.databaseConnect(Installer.java:613)
at org.opennms.install.Installer.install(Installer.java:195)
at org.opennms.install.Installer.main(Installer.java:2450)
i have just now checked my postgre with command "netstat -anp | grep
"post"" and they are right:
udp 0 0 127.0.0.1:32968 127.0.0.1:32968
ESTABLISHED 5850/postmaster
unix 2 [ ACC ] STREAM LISTENING 123166
5850/postmaster /tmp/.s.PGSQL.5432
why dont my opennms setup datebase successfully on my postgresql?