Spamassassin for RHEL 4 should be upgraded to version 3.1.x to provide support for the sa-update utility. The sa-update utility provides a conveninent method to update the rules and scores used by spamassassin to detect spam. Spam filter rules like anti-virus definitions need to be updated regularly.
I asked and this was rejected earlier. RHEL4 lacks dependencies to make sa-update work. We may upgrade spamassassin to a 3.1.x version at a later date if product management approves of it, but this is currently not in the near-term plans. spamassassin-3.1.4 is already heading towards with RHEL5 with optional deps to use sa-update.