authentication

Hi all,
 I Tried to test ldap authentication of the proxy using polymix.
i downloaded and installed polygraph 2.8.0.

This is the robot configuration in the polymix-4-guts.pg file.

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// describe PolyMix-4 robot
Robot R = {
        kind = "PolyMix-4-rbt";

        recurrence      =  55%/HitIfRepeat; // recurrence is not hit ratio
        embed_recur     = 100%;
        interests = [ "public": 75%, "private" ];
        pop_model = popModel;

        req_types = [ "Basic", "Ims200": 5%, "Ims304": 10%, "Reload" : 5% ];
        req_methods = [ "GET", "POST" : 1.5%, "HEAD" : 0.1% ];
        abort_prob = 0.1%;

        req_rate = TheBench.client_side.max_agent_load;
        pconn_use_lmt = zipf(64);
        open_conn_lmt = 4;

*  **     credentials = [ "StoogeAdmin:secret1" ];*
        dns_resolver = Resolver;
        origins = Map.names;
        addresses = robotAddrs(asPolyMix4, TheBench);
        http_versions = [ "1.0" ];  // newer agents use HTTP/1.1 by default
};
---------------------------------

StoogeAdmin and secret1 are the username and password for the ldap server
which needs to be authenticated.
But i used dump errs in the client side and i received the 401 
unauthorised message.
I am not sure whether i need to make any more modifications other than 
adding the
credentials.Could any1 help me on this??

Regards,
Senthil