[Dovecot] Unknown dict module: db

Using dovecot-1.1beta1 I get "Unknown dict module: db" when starting up dovecot. In dovecot.conf I've got the "expire_dict = db:/var/lib/dovecot/expire.db" statement in the plugin{} section. Aparently required when the "expire" plugin is enabled. dovecot is built with "--with-db" and db-devel is present at compile time.

Any ideas anyone?

Cheers /Lars