Problem with Forms Authentication

Hi,
 Iam having problem with Forms authentication. I have the login page in the sub folder. Let me give the folder structure.
I have the following folder structure.
Root folder

    -   Default.aspx (This is the home page of the site contains link for login.aspx (which is in another folder UI)
   -    web.config
                    
    -   UI
           -  login.aspx
           -  some static pages

          -   Admin (folder)
          -   Templates (folder) for master pages

 Here login is for a ...