ERROR 256: DB connection error in PGV_DB::createInstance(): SQLSTATE[HY000] [2002] Can't connect to local server through socket '/var/lib/mysql/mysql.sock' (2)

Fatal error: DB connection error in PGV_DB::createInstance(): SQLSTATE[HY000] [2002] Can't connect to local server through socket '/var/lib/mysql/mysql.sock' (2) in /home/nikielm/sites/nikiel.net/www/drzewo/includes/classes/class_pgv_db.php on line 405