ERROR 256: DB connection error in PGV_DB::createInstance(): SQLSTATE[HY000]: General error: 2006 MySQL server has gone away

Fatal error: DB connection error in PGV_DB::createInstance(): SQLSTATE[HY000]: General error: 2006 MySQL server has gone away in /data/www/PGV/includes/classes/class_pgv_db.php on line 405