I found that Cloudmark was disabling my AVG antivirus email scanning, so I had to uninstall it. Dang. I liked that program.
Then I discovered that I could change the exim settings on my dedicated server so that it checks the IP address of all incoming mail against the Spamcop.com database of IP addresses of "known spammers" before it accepts the email. I implemented that and everyone on my server is much happier with the dramatic decrease in spam overall.
Now I receive less than 50 spams a day, and those are easily sorted by AVG's mail scanner. So Cloudmark is not really needed after all.