>>TBH I'm not au fait with all of the CredentialCache stuff. If I were you I'd try creating your own credentials and using that:

>>Req.Credentials = new NetworkCredential("UserName", "password"); // or other relevant constructor

>
>So create a user on the server with the necessary rights, then set the code to use this user? I don't particularly like that idea for the following reasons: I then need to hard code the password in, I need to work out what rights to assign to the user on the server. If somebody then changes the password on the server I have to recompile my code. Or am I misunderstanding what you suggested?

So the web server at the oAppSettings.ReportServerURL address is under your control? So what is it currently expecting/accepting as a valid authentication/authorisation ?