Flash Media Live Encoder Authentication Add-In not working

I have installed the Authentication Add-In on a FMS 3.5.5 Development version, running Windows 2008 Server.  I can easily get to the users.exe command prompt and add users with no problem.  BUT, when I open the Flash Media Live Encoder and go to enter a username/password when connecting to the server, I keep getting "User Not Found".  I've went back several times using users.exe and tested for my user credentials and it always states that the user is there.  Can some please tell me what I am doing wrong here?