Can't run postmaster with 6.5.1

Hi,
I have postgresql, postgresql-clients, postgresql-data, postgresql-devel of
release 6.3.2-10 on my redhat linux 5.2. I uninstalled them and installed
postgresql, postgresql-devel, postgresql-server, postgresql-jdbc,
postgresql-perl of release 6.5.1-2. But when I run su -l postgres -c
'/usr/bin/postmaster -S -D/var/lib/pgsql', I have the following error:
/usr/bin/postmaster does not find the database system. Expected to find it in
the PGDATA directory "/var/lib/pgsql", but unable to open file with pathname
"/var/lib/pgsql/base/template1/pg_class".
Where can I download postgresql-data6.5.1-2? Do I need
postgresql-clients6.5.1-2?

Thanks in advance,

Leon Yu