[Dovecot] help with expire plugin

[Joy]

Dear All,
              I am using version 2.0 and willing to use expire plugin
in my setup but unable to set it up correctly. Here is the relevant
part from output of doveconf -n

# 2.0.0: /usr/local/dovecot/etc/dovecot/dovecot.conf
# OS: Linux 2.6.26-2-686 i686 Debian 5.0.6
base_dir = /usr/local/dovecot/var/run/dovecot/
dict {
  expire = mysql:/etc/dovecot/dovecot-dict-sql.conf.ext
}
mail_plugins = quota acl expire virtual

namespace {
  inbox = yes
  location =
  prefix =
  separator = .
  type = private
}

plugin {
  expire = Trash 7 Spam 30
  expire_dict = proxy::expire
}

}

protocol imap {
  mail_plugins = $mail_plugins imap_acl autocreate imap_quota
}


I have also created the database and tables for mysql and made the
following change in dovecot-dict-sql.conf.ext file

connect = host=localhost dbname=mails user=root password=xxxxxx

map {
  pattern = shared/expire/$user/$mailbox
  table = expires
  value_field = expire_stamp

  fields {
    username = $user
    mailbox = $mailbox
  }
}


I am not getting any error in log file and expire is not working too
please let me know the issue ...

Thanks