Are you using the current version or a previous version? Because that feature was only implemented in the 3.4 version, and you are posting in the previous version forum.
Anyways, only the admin that is specified in your config.asp file can access the mod setup.
Around lines 76 in your config.asp file, you should see the following:
Const intAdminMemberID = 1
Change the 1 to the id of the admin account you use.
You can find the member id by viewing your profile. You will see the ID in the url.