Hans, I posted a workaround that ensures the C locale is used for the PG database and server using PG 7.1.2 RPMs in another thread recently. Essentially you can do
echo LANG=C >>/etc/sysconfig/i18n
and then install the Postgresql RPMs for the "first time" (ie you must NOT have a PG database already existing, rm -rf /var/lib/pgsql
if necesary). Once the postgresql-server RPM is installed and you start PG for the first time, you can then remove the LANG=C line from the /etc/sysconfig/i18n
file once more.