Answered MODX PageLocker only works for 24 hours

<?php
$pagelocker = $modx->getService('pagelocker','PageLocker',$modx->getOption('pagelocker.core_path',null,$modx->getOption('core_path').'components/pagelocker/').'model/pagelocker/',$scriptProperties);
if (!($pagelocker instanceof PageLocker)) return '';

unset($_SESSION['password']);  // make sure password is not still set

unset($_SESSION['password']);  // make sure password is not still set
unset($_SESSION['loggedin']);    // make sure user is not logged in

/* Do nothing if page is not password-protected, or the form page is not set in the properties */
if ((empty($resourcePW)) || (empty($formResourceID))) { 
    return;
}

$tvPassword = $modx->getOption('tvPassword',$scriptProperties,'pagePassword');
$tvPasswordGroup = $modx->getOption('tvPasswordGroup',$scriptProperties,'pagePasswordGroup');

$tvPassword = $modx->getOption('tvPassword',$scriptProperties,'pagePassword', true);
$tvPasswordGroup = $modx->getOption('tvPasswordGroup',$scriptProperties,'pagePasswordGroup', true);

[2014-10-09 11:20:07] (ERROR @ /usr/local/home/httpd/vhtdocs/domainname.co.uk/core/cache/includes/elements/modplugin/4.include.cache.php : 106) PHP warning: Cannot modify header information - headers already sent by (output started at /usr/local/home/httpd/vhtdocs/domainname.co.uk/core/model/modx/modresponse.class.php:189)