According to my host, their mod_security rules are not outdated.
Rather, they think it might be a conflict with some of the custom rules they are using.

Do you think this could be the case?

How do I prevent guests from viewing the userlist of my PunBB installation?

Thanks Smartys. I've contacted my host to see if they can update the mod_security rules.
I'll keep you posted.

Here's what it says in the error log:

[Mon Apr 17 18:24:09 2006] [error] [client x] mod_security: Access denied with code 500. Pattern match "profile\\\\.php\\\\?section=admin\\\\&id=.*\\\\&action=foo" at REQUEST_URI [hostname "x"] [uri "/profile.php?section=admin&id=3&action=foo"] [unique_id "x"]

I've replaced some sensitive information with a single 'x'.

I am running PunBB 1.2.11 on Apache/PHP 4.3.10/MySQL 3.25.58.

When I try to move a member to a different user group (i.e. from 'Members' to 'Moderators') I get an Internal Server Error.

Internal Server Error
The server encountered an internal error or misconfiguration and was unable to complete your request.

Please contact the server administrator to inform of the time the error occurred and of anything you might have done that may have caused the error.

More information about this error may be available in the server error log.

The URL it tries to access is: /profile.php?section=admin&id=3&action=foo

I haven't encountered any other errors or problems so far.
Does anyone have a clue as to what could be the problem here?

On another note: Any way to prevent guests from viewing the user list?

[edit]Some spelling. wink[/edit]