I really don’t understand the question fully But here it goes…<img src=icon_smile.gif border=0 align=middle>
If you did turn off Anonymous access for the folder for the forum. And you are still getting “You have to enable non-Anonymous access for the forum on the server first” Message. Then I need to know what version you are working with. This was a problem in the code but I believe it was updated. You can always go to into the database and just change the mode manualy.
Also when you connected to the web page to change to NT mode, did the web page ask for a name and password? It should if you are on the Internet. If on a Intranet go to Admin Options, Server information, and check the AUTH_USER, Is this set to anything? If you are running with Anonymous access off, you should have an account name here.
FYI
NT Mode is mostly used on Intranets. If you are trying to use this on the Internet, you could set to NT mode, but then you would have to create an account for each user on the server, I would not run NT mode on the Internet