Uncaught TypeError: Cannot read property 'error' of null

Hello, i get this error in the console: (Uncaught TypeError: Cannot read property 'error' of null), from what i have read in the forums it is due to utf8_encoding, i have tried to force the encoding as other users suggested by modifying this:

        $pdo = @new PDO(
            "mysql:host={$host};{$port}dbname={$db}".self::dsnPostfix( $dsn ),
            //"mysql:host={$host};{$port}dbname={$db}".self::dsnPostfix( $dsn ).";charset=utf8",
            $user,
            $pass,
            array(
                PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION
            )
        );

        $pdo->query('SET CHARACTER SET utf8');
        $pdo->query('SET NAMES utf8');

But it still does not work, do you have any suggestions?