Error while changing authentication in cupsd.conf

[vipul mahajan]

Hello,

I was trying to change the authentication by putting check as follows:
<Location />
  AuthType Basic
  Require user admin
  # Allow remote access...
  Order allow,deny
  Allow all
</Location>

but when i click "Add Printer" in Administration or any other option I get error message on GUI.

Please let me know the correct way of doing.