For some reason Server admin from 10.6.6 screws the dovecot config file up.
Make sure you Certificate has NO spaces in the name
Quit SA
edit /etc/dovecot/dovecot.conf and look for the line that start ssl_
Remove all paths to certificates
Start SA and select you SSL for IMAP. Click Save and quit SA
go back to the dovecot.conf and remove the # at the start of the ssl_ lines that now have paths
restart SA and all should be good