The installation of spamassassin failed at first because I couldn't resolve the dependencies of spamassassin 2.40 . I succeeded later in installing spamassassin 2.55 . This howto and an extra rpm (openssl-0.9.6b-3.i386.rpm), and the re-creation of two links did the job.
Spamassassin does its job real good. I've upgraded the scores for Pyzor and DCC to just above 5, mail that is in those databases shouldn't be approved. I've had no false positives yet.