ERROR 256: DB connection error in PGV_DB::createInstance(): SQLSTATE[HY000] [2002] No such file or directory

Fatal error: DB connection error in PGV_DB::createInstance(): SQLSTATE[HY000] [2002] No such file or directory in /www/htdocs/w007840b/phpgedview-4.3.1/includes/classes/class_pgv_db.php on line 405