pg_dump problem

I'm trying to migrate a PostgreSql 8.3 database from a Windows 2003
server to a PostgreSql 8.4 Linux x86_64 server running Ubuntu Server
12.04.

When running pg_dump from the Linux server, I get:

postgres(at)ubuntupostgresql:~$ pg_dump -h 192.168.10.105 -U postgres ris
pg_dump: SQL command failed
pg_dump: Error message from server: ERROR: unrecognized configuration parameter "synchronize_seqscans"
pg_dump: The command was: SET synchronize_seqscans TO off

I've read in older mails that this massage shows when one side is
running EnterpriseDB version of PostgreSql and the other is running a
PostgreSql version. I must point out this is not my case, both sides are
running PostgreSql versions, the Linux side is running the one from the
official repository, and the Windows one is running an old 8.3 version
downloaded from postgresql.org.

Any hint?.

Regards,
--
Leonardo M. Ramé
Medical IT - Griensu S.A.
Av. Colón 636 - Piso 8 Of. A
X5000EPT -- Córdoba
Tel.: +54(351)4246924 +54(351)4247788 +54(351)4247979 int. 19
Cel.: +54 9 351 6629292