[Asterix]

just copy this code:

// receiving script...
//
// You need to pass the value of $task from the calling script to the receiving script. While
// this may appear dangerous, it still only allows a one shot at the receiving script, which
// effectively stops flooding.
// page verify by retro
class page_verify
{
    function __construct()
    {
        if (session_id() == '') {
            session_start();
        }
    }
    function create($task_name = 'Default')
    {
        global $CURUSER, $_SESSION, $INSTALLER09;
        $session_task = isset($CURUSER['id']) ? $CURUSER['id'] : $INSTALLER09['bot_id'];
        $_SESSION['Task_Time'] = TIME_NOW;
        $_SESSION['Task'] = md5('user_id:'.$session_task.'::taskname-'.$task_name.'::'.$_SESSION['Task_Time']);
        $_SESSION['HTTP_USER_AGENT'] = isset($_SERVER['HTTP_USER_AGENT']) ? $_SERVER['HTTP_USER_AGENT'] : '';
        //$_SESSION['HTTP_USER_AGENT'] = $_SERVER['HTTP_USER_AGENT'];
    }
    function check($task_name = 'Default')
    {
        global $CURUSER, $INSTALLER09, $lang, $_SESSION;
        $returl = (isset($_SERVER['HTTP_REFERER']) ? htmlsafechars($_SERVER['HTTP_REFERER']) : $INSTALLER09['baseurl']."/login.php");
        $returl = str_replace('&', '&', $returl);
        if (isset($_SESSION['HTTP_USER_AGENT']) && $_SESSION['HTTP_USER_AGENT'] != $_SERVER['HTTP_USER_AGENT']) stderr("Error", "Please resubmit the form. <a href='".$returl."'>Click HERE</a>", false);
        $session_task_id = isset($CURUSER['id']) ? $CURUSER['id'] : '';
        if (isset($session_task) && $session_task != md5('user_id:'.$session_task_id.'::taskname-'.$task_name.'::'.$_SESSION['Task_Time'])) stderr("Error", "Please resubmit the form. <a href='".$returl."'>Click HERE</a>", false);
        $this->create();
    }
}
?>

and save as page_verify.php on /include/class/.
verify on config.php if you have this line.
$INSTALLER09['bot_id'] = 2;