There are no readable files in this directory tree. Are safe mode or open_basedir active?

ojs2 has produced an error
  Message: WARNING: file_exists(): open_basedir restriction in effect. File(/) is not within the allowed path(s): (/home/litbang/wwwroot/pemas.unisla.ac.id/:/home/litbang/tmp/:/tmp/:/home/litbang/wwwroot/files)
  In file: /home/litbang/wwwroot/pemas.unisla.ac.id/lib/pkp/classes/file/FileManager.inc.php
  At line: 350
  Stacktrace: 
  Server info:
   OS: Linux
   PHP Version: 5.6.40
   Apache Version: N/A
   DB Driver: mysql
   DB server version: 10.11.16-MariaDB-log<br/>
<h1>There are no readable files in this directory tree. Are safe mode or open_basedir active?</h1>