Hello, I found that, in order to works, the solution needs extra edit, from $db to $forum_db

// Check if InnoDB is available
    if ($db_type == 'mysql_innodb' || $db_type == 'mysqli_innodb')
    {
        $result = $forum_db->query('SELECT SUPPORT FROM INFORMATION_SCHEMA.ENGINES WHERE ENGINE = \'InnoDB\'');
        list ($result) = $forum_db->fetch_row($result);
        if (!in_array($result, array('YES', 'DEFAULT')))
            error($lang_install['InnoDB off']);
    }