[Dovecot] Error using antispam plugin

Hi

When activating antispam plugin in imap protocol, when sending an email, Evolution/Thunderbirdkeeps infinitely "Sending authentication information", and Dovecor logs shows "dovecot: May 28 10:14:35 Error: child 6910 (imap) killed with signal 11"; lots of empty folders in /tmp are created with names like "antispam-mail-ZvyWeZ".

I am using Dovecot1.1 rc15 compiled from Debian source repositories (http://xi.rename-it.nl/debian/) and last version of antispam plugin, obtained with git. Any idea or help to debug?

Thanks.