failed to open dir: No such file or directory when hosting

Question

In localhost I can add,edit, copy my folder and files ,but after I post in hosting web , those functions don't work on the server.

Warning: opendir(../../data/chapters/PLH8G-BmfHh-ccc0h-Vp7wh): failed to open dir: No such file or directory in /home/vol17_2/ezyro.com/ezyro_32005085/htdocs/render/public/chapter.req.php on line 35

Warning: readdir() expects parameter 1 to be resource, bool given in /home/vol17_2/ezyro.com/ezyro_32005085/htdocs/render/public/chapter.req.php on line 36

$files = array();
$dir = opendir("../../data/chapters/".$chapter["slug"]); // open the cwd..also do an err check.
while(false != ($file = readdir($dir))) {
    if(($file != ".") and ($file != "..") and ($file != "index.php")) { 
        $files[] = $file;