error writing file on remote server in WCF
===

I'm creating a WCF (C#, VS2010) for my silverlight app, I'm trying to create a file on my remote server (where WCF exists), but I get an unknown error, I just get "Server not found" error in WCF function complete exception message, I use following codes to create a file on my remote server (I use a VDS, so I think I don't have permission problems, I use remote desktop on my server)

                using (StreamWriter outfile =
                new StreamWriter("mytest.htm"))
                {
                    outfile.Write(body);
                }

what is going wrong here? is it possible that I have permission problems? I run my WCF on local system and it creates file successfully, but there is no luck when it is uploaded to remote server