"Message not checked due to license limmitations" after upgrade

[tictoc@]

I have just upgraded one of my servers from Plesk 8.0.1 to Plesk 8.2. After the upgrade I am now getting emails from the DrWeb-DAEMON titled "A message has not been checked due to license limitations" from occasional emails. Part of the email details has lines like:

127.0.0.1 [10596] drweb.tmp.oP8Fa0 - message's envelope (addresses) aren't present in license (protected e-mail`s), skipped!

We have a license for SpamAssassin that was working fine before the upgrade. I'm assuming it's something to do with that?

Any suggestions for a fix/work-around?