Dedicated Administrator Connection

Hi:

I am trying to connect to my local instance of SQL Server 2005 using Dedicated Administrator Connection by using

Admin:Servername\Instancename

and I end up with the following error.

Dedicated administrator connections are not supported.

I enabled the connection in the SQL Configuration Manager and still get the error.

Any ideas on how to resolve this error?.

Note: SQL Browser service is running.

Thanks

Ak