score-0 problem: SpamAssassin (not cached, score=0, required 5, autolearn=)

[donald.dawson]

I have noticed that some spam has been creeping in.  We have 4 inbound
MX servers, but only has is experiencing this problem.

SpamAssassin version 3.2.0
running on Perl version 5.8.3
This is MailScanner version 4.59.4

Here are the counts of 'is not spam' and 'is spam' with 'score=0,':

fgrep "score=0," /var/log/maillog | grep 'is not spam' | wc -l -- 649
fgrep "score=0," /var/log/maillog | grep 'is spam' | wc -l -- 311

Spamassasin is not showing any errors, and '/usr/bin/spamassassin -D -p
/etc/MailScanner/spam.assassin.prefs.conf --lint' does not show errors.

Here is an example of the headers from a spam message:

From: "Erick Page" <[EMAIL PROTECTED]>
X-Mailer: The Bat! (v2.01) Personal
Reply-To: [EMAIL PROTECTED]
X-Priority: 3 (Normal)
Message-ID: <[EMAIL PROTECTED]>
To: [EMAIL PROTECTED]
Subject: Greatest artworks from top artists
MIME-Version: 1.0
Content-Type: multipart/alternative;
  boundary="----------F6EBF6EB821E4B82"
X-Null-Tag: fca71ee22f4011b5a8b9f02a21610260
X-BakerBotts-MailScanner-Information: Please contact the ISP for more
information
X-BakerBotts-MailScanner-SpamCheck: not spam, SpamAssassin (not cached,
        score=0, required 5, autolearn=)
X-BakerBotts-MailScanner-From: [EMAIL PROTECTED]
X-Spam-Status: No
Return-Path: [EMAIL PROTECTED]

I would appreciate any help you can provide.

Thanks,
Donald

Donald Dawson
Security Administrator
Baker Botts L.L.P.
713-229-2183