You need another plugin configurated to make sure the comment system is working fine. Please down load it here: http://www.box.net/shared/guzaltqo8k

then go to this url:
    {youblog.com}/wp-admin/options-general.php?page=briansthreadedcomments.php
    and enter ˇ°wp-comments-post.phpˇ± in ˇ°Custom Comments Target:ˇ±

Thanks to Brian's great plugin!