Không biết có đúng box không nhưng mong các bạn vô coi lỗi dùm

khi vào web index:
Fatal error: Class 'XenForo_ControllerPublic_Abstract' not found in C:\xampp\htdocs\beta\library\XenForo\ControllerPublic\Index.php on line 3


Sau đây là nội dung index:

<?php

class XenForo_ControllerPublic_Index extends XenForo_ControllerPublic_Abstract
{
public function actionIndex()
{
$this->canonicalizeRequestUrl(
XenForo_Link::buildPublicLink('index')
);

$viewParams = array(
'nodeList' => $this->_getNodeModel()->getNodeDataForListDisplay(false, 0),
'onlineUsers' => $this->_getSessionActivityList(),
'boardTotals' => $this->_getBoardTotals()
);

return $this->responseView('XenForo_ViewPublic_Forum_List', 'forum_list', $viewParams);
}

protected function _getSessionActivityList()
{
$visitor = XenForo_Visitor::getInstance();

$sessionModel = $this->getModelFromCache('XenForo_Model_Session');

return $sessionModel->getSessionActivityQuickList(
$visitor->toArray(),
array('cutOff' => array('>', $sessionModel->getOnlineStatusTimeout())),
($visitor['user_id'] ? $visitor->toArray() : null)
);

}

protected function _getBoardTotals()
{
$boardTotals = $this->getModelFromCache('XenForo_Model_DataRegistry')->get('boardTotals');
if (!$boardTotals)
{
$boardTotals = $this->getModelFromCache('XenForo_Model_Counters')->rebuildBoardTotalsCounter();
}

return $boardTotals;
}

/**
* Session activity details.
* @see XenForo_Controller::getSessionActivityDetailsForList()
*/
public static function getSessionActivityDetailsForList(array $activities)
{
return new XenForo_Phrase('viewing_forum_list');
}

/**
* @return XenForo_Model_Node
*/
protected function _getNodeModel()
{
return $this->getModelFromCache('XenForo_Model_Node');
}
}