Hi Dear, My code is here. Just have a look it. there is one method named GetSearchResults_soap it have 4 param I am passing it properly and hardcoded just my changed code is srch.AuthHeader au = new srch.AuthHeader(); // This is a class file au.UserName = Compute("pradeepraon@hotmail.com"); // property au.Password = Compute("srch10242"); // property srch.Srch test = new srch.Srch(); // main class file who has that method which we I am calling. srch.SearchResults s = new srch.SearchResults(); //searchresult class //When I am calling this GetSearchResults_soap method at that time it is throwing an error. that server was unable to process request and object ref. not set to an instance of an object. s = test.GetSearchResults_soap("hotels", "bangalore", 1, 500);//error line