You'll need to add the following to /etc/rc.d/rc.local (and make
sure /etc/rc.d/rc.dictd is executable):

  if [ -x /etc/rc.d/rc.dictd ]; then
    /etc/rc.d/rc.dictd start
  fi

You might also want to add this to /etc/rc.d/rc.local_shutdown
(create that file if it doesn't exist, and make it executable):

  if [ -x /etc/rc.d/rc.dictd ]; then
    /etc/rc.d/rc.dictd stop
  fi