Welcome to 4images forum.
I don't have this mod installed, it's not tested:
in shout.php find:
$site_template->register_vars(array("errormsg"=>$errormsg));
}
unset ($errormsg);
Replace with:
$site_sess->set_session_var("shoutmsg", $errormsg);
redirect("shout.php");
}
$errormsg = $site_sess->get_session_var("shoutmsg");
$site_template->register_vars("errormsg", $site_sess->get_session_var("shoutmsg"));
unset ($errormsg);