spamassassin no longer being called?

[Jay Kusler]

I'm puzzled.

Yesterday I upgraded spamassassin from 2.31 to 2.55 (and then to 2.60).  It
appears now that
spamassassin is not being called any longer.  All messages have the
X-MailScanner-SpamCheck:
with 'SpamAssassin (score=0, required 6)'.  If I pipe the same message into
spamassassin from
the command line (spamassassin < message), then spamassassin's
X-Spam-Status: header shows
a score of something other than 0.  Invoking spamassassin from a .procmailrc
recipe also correctly scores the messages.  I believe I have the right stuff
set in MailScanner.conf:
Log Spam = yes
Use SpamAssassin = yes
Check SpamAssassin If On Spam List = yes
Always Include SpamAssassin Report = yes
Spam Score = yes
Spam Checks = yes

Solaris 8
Postfix 2.0.11
MailScanner 4.21-9
Spamassassin 2.60 (same results with 2.55)

Any ideas where I can look?

Thanks

Jay Kusler