A reinstall seems somewhat drastic here. The "dead but subsystem locked" message means that the server crashed but did not remove the /var/lock/subsys/dovecot file (on Red Hat distros). A simple "service dovecot start" should get it going again. If you're using the 0.99 release distributed with some Red Hat releases, you might want to try upgrading to the 1.0 betas as they include a whole lot of improvements. See
www.dovecot.org for details.
