Cakephp错误：发生了内部错误

这是PHP控制器：

$this->loadModel( 'Vote' ); //Newly added by amit start
$vote=$this->Vote->getVote($id,$uid);
$this->set('vote',$vote);
$voteCount = count($vote);
$this->set('voteCount',$voteCount);

$voteShow = $this->Vote->find('all',array(
    'fields' => array('SUM(Vote.score)   AS score','count(id) as countId'),'conditions'=>array('Vote.type_id'=>$id),));
$this->set('voteShow',$voteShow);

模型：

public function getVote($id,$uid) {
    if (empty($conditions))
        $conditions = array('Vote.type' => 'blog','Vote.type_id' => $id,'Vote.user_id' => $uid);

    $users = $this->find('all',array('conditions' => $conditions,'order' => 'Vote.id desc'
    ));
    return $users;
}

该代码产生此错误：

Error : An internal error has occurred

这个错误是什么意思？