Thank you Mamba!. I have installed the module and i obtained this error:
Array to string conversion nel file /modules/newbb/include/module.php at line 52
Is impossible add new moderator after first selection. In admin_forum_manager.php there this deprecated class: Class 'XoopsTree' is deprecated, check 'XoopsObjectTree' in tree.php
Try with module backup, i converted all db in utf-8. The module can't modify or broken system database, you can create one copy in other database. If all is correct, set the copy database as the system and modofy old system db.
The captcha code can be set in core setting, you must setting it in class/captcha modify the file: config.php and config.recaptcha.php (if you want use recaptcha you can add key of google in this file).
For able security code you must able it in the admin xfguestbook module. The secure code, work only for anonymous users (this is a problem of the core).
You can see the module working in a photography website that i'm doing: