com.google.gdata.util.AuthenticationException: Error authenticating (check service name)

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What steps will reproduce the problem?
I am trying to create a GSA CLIENT object. i have entered the arguments as 
below.
1.gsaClient = new GsaClient("152.96.99.41",8000, "user", "pwd");

i get the below error

com.google.gdata.util.AuthenticationException: Error authenticating (check 
service name)
    at com.google.gdata.client.GoogleAuthTokenFactory.getAuthException(Unknown Source)
    at com.google.gdata.client.GoogleAuthTokenFactory.getAuthToken(Unknown Source)
    at com.google.gdata.client.GoogleAuthTokenFactory.setUserCredentials(Unknown Source)
    at com.google.gdata.client.GoogleService.setUserCredentials(Unknown Source)
    at com.google.gdata.client.GoogleService.setUserCredentials(Unknown Source)
    at com.google.enterprise.apis.client.GsaClient.<init>(Unknown Source)
    at com.google.enterprise.apis.client.GsaClient.<init>(Unknown Source)
    at sample.aclclient.AclClient.main(AclClient.java:149)
-------------------------------------------------------------------------
Do i need to make any configuration changes in GSA like adding my local systems 
address in trusted ip.

please help me for the same

Original issue reported on code.google.com by anu13tra...@gmail.com on 19 Oct 2010 at 2:04