Warning: require(application/config/constants.php): failed to open stream: No such file or directory in /var/www/html/app1/system/core/CodeIgniter.php on line 64

Fatal error: require(): Failed opening required 'application/config/constants.php' (include_path='.:/usr/share/pear:/usr/share/php') in /var/www/html/app1/system/core/CodeIgniter.php on line 64