Nobody can access the showgroups.php page

[Fresky]

Dear friends,

We at our forum have a problem. It has occured suddenly, nobody can access the showgroups.php page (i think this is called the Forum Leaders page).

When somebody, from regular users to admins, tries to access this page, he gets the following error:

<username>, you do not have permission to access this page. This may be one of several reasons:

1. Your user account may not have sufficient privileges to access this page. Are you trying to edit a message from another user, access administrative features or some other privileged system?
2. If what you're trying to haceer, is to create a new message, the administrator may have disabled your account, or it may be awaiting activation.

I have checked all the groups, and the permissions set in the "User group options" sections, and are all ENABLED IN ALL GROUPS.

I have uploaded the page from my computer to the server. No way.

I have tried to change the permissions using Dreamweaver. No way.

What else can I do?

Is there any other section/setting in vbulletin that controls the access to this page???????

The only thing that I remember did just before this problem, was to delete two groups with no users, in order to clean up our group organization. Do you think could it be the problem?

How can I solve it?

I am really desperated with this issue. Any help will be very very appreciated.

We are running 3.8.1

Regards.