Hi,
Are they in a group that has MOderator powers over any forum.
One option is to go to the Admin CP -> USer Admin -> Permissions and set them as Admin. Then submit. Then set as USer and submit.
Or you can check the database in the user table and make sure that each user level for these members is 0 and not 2 set it to 0 if it is.
Hope this helps,
Des. . .