如何在codeigniter重命名文件夹中重命名文件夹不起作用

In my project i have language folder. if new language created a new folder will generate. And if we want to rename language, its folder should be rename.

$res =  $this->db->get_where('languages',array('l_id'=>$data['id']))- 
>result_array();    
rename(APPPATH.'/language/'.$result[0]['l_eng'], $data['l_eng']);