I am using the 'Users and Roles' feature (7.0.0).  The DNN base version is on 7.0 now.  I try to add a new user and the dialog doesn't dismiss as if nothing happens.  When I try again, it says the user already exists with the username I'm supplying.  However, I cannot find this user when I view all of them.  I am not sure if I reached some sort of limit or what.  This happens every time I try to add a new user