pg_dump problem

Hi All,

today I ve got this error during a backup:

[root@foradada root]# pg_dump -U postgres radiuslog | gzip -c > 
radiuslog-20041116.gz
pg_dump: ERROR:  unknown address family (3)
pg_dump: lost synchronization with server, resetting connection
pg_dump: SQL command to dump the contents of table "radacct" failed: 
PQendcopy() failed.
pg_dump: Error message from server: pg_dump: The command was: COPY 
public.radacct (radacctid, acctsessionid, acctuniqueid, username, realm, 
nasipaddress, nasportid, nasporttype, acctstarttime, acctstoptime, 
acctsessiontime, acctauthentic, connectinfo_start, connectinfo_stop, 
acctinputoctets, acctoutputoctets, calledstationid, callingstationid, 
acctterminatecause, servicetype, framedprotocol, framedipaddress, 
acctstartdelay, acctstopdelay) TO stdout;

what can I do to resolve the problem?

This on RH9 updated and PostgreSQL v7.3.4

Thanks in advance.

Roberto Fichera.