Error while downloading.

public bool GetSFTP()
        {
            string filename = string.Empty, outfilename = null, output = null, errmsg = null;

            // Run hidden WinSCP process
            Process winscp = new Process();
            string logname = Path.ChangeExtension(Path.GetTempFileName(), "xml");
            var _with1 = winscp.StartInfo;
            // SFTPExecutable needs to be defined in app.config to point to winscp.com
            try
            {
                _with1.FileName = ConfigurationSettings.AppSettings["SFTPExecutable"].ToString();
                if (_with1.FileName == null || _with1.FileName.Length == 0)
                {
                    EventLog.WriteEntry(logSource, "from GetSFTP: SFTPExecutable not set in config file.", EventLogEntryType.Warning);
                    throw (new Exception("from GetSFTP: SFTPExecutable not set in config file."));
                }
            }
            catch (Exception ex)
            {
                errmsg = ex.Message;
                EventLog.WriteEntry(logSource, errmsg, EventLogEntryType.Error);
                return false;
            }
            _with1.Arguments = "/log=" + logname;
            _with1.UseShellExecute = false;
            _with1.RedirectStandardInput = true;
            _with1.RedirectStandardOutput = true;
            _with1.CreateNoWindow = true;
            try
            {
                winscp.Start();
            }
            catch (Exception ex)
            {
                EventLog.WriteEntry(logSource, "from GetSFTP: Could not run the WinSCP executable.", EventLogEntryType.FailureAudit);
                errmsg = "from GetSFTP:  Could not run the WinSCP executable " + winscp.StartInfo.FileName + Environment.NewLine + ex.Message;
                return false;
            }

            // Feed in the scripting commands
            var _with2 = winscp.StandardInput;
            _with2.WriteLine("option batch abort");
            _with2.WriteLine("option confirm off");
            //_with2.WriteLine("open sftp://" + username + ":" + password + "@" + remotehost);
            _with2.WriteLine(" open " + Protocol + "://" + Username + "@" + Hostname + ":" + Port + " -privatekey=\"" + PublicKeyPath + "\"");
            _with2.WriteLine("cd /entitlement/ENT_7005");
            //_with2.WriteLine("put C:\\Ahsan_Test\\fwfi.log \"" + defaultRmDir + "\"");
            //_with2.WriteLine("exit");
            /*
            filename = "C:\\Ahsan_Test\\fwfi.log";
            if (outfilename == null)
                _with2.WriteLine("put " + filename);
            else
                _with2.WriteLine("put " + filename + " \"" + outfilename + "\"");
            */
            _with2.WriteLine("ls");
            _with2.WriteLine("get \"fwis.xml\" \"" + defaultLocalDir + "\"");
            _with2.Close();
            
            //Get winscp output
            //if ((output != null))
                output = winscp.StandardOutput.ReadToEnd();
            MessageBox.Show(output);
            // Wait until WinSCP finishes
            winscp.WaitForExit();

            // Parse and interpret the XML log
            // (Note that in case of fatal failure the log file may not exist at all)
            if (!File.Exists(logname))
            {
                errmsg = "from GetSFTP:  The WinSCP executable appears to have crashed.";
                EventLog.WriteEntry(logSource,errmsg, EventLogEntryType.FailureAudit);
                return false;
            }

            XPathDocument log = new XPathDocument(logname);
            XmlNamespaceManager ns = new XmlNamespaceManager(new NameTable());
            ns.AddNamespace("w", "http://winscp.net/schema/session/1.0");
            XPathNavigator nav = log.CreateNavigator();
           
            // Success (0) or error?
            bool status = (winscp.ExitCode == 0);
            MessageBox.Show(status.ToString());
            if (!status)
            {
                errmsg = "from GetSFTP:  There was an error transferring " + filename + ".";
                // See if there are any messages associated with the error
                foreach (XPathNavigator message in nav.Select("//w:message", ns))
                {
                    errmsg += Environment.NewLine + message.Value;
                }
            }

            try
            {
                File.Delete(logname);
            }
            catch (IOException ex)
            {
                MessageBox.Show(ex.Message, "SFTP", MessageBoxButtons.OK, MessageBoxIcon.Error);
                EventLog.WriteEntry(logSource, ex.Message, EventLogEntryType.FailureAudit);
                // at least we tried to clean up
            }

            return !status;
        }

<?xml version="1.0" encoding="UTF-8"?>
<session xmlns="http://winscp.net/schema/session/1.0" name="username@hostname" start="2011-01-13T11:29:30.341Z">
  <download>
    <filename value="/entitlement/fwis.xml" />
    <destination value="C:\Ahsan_Test\fwis.xml" />
    <result success="true" />
  </download>
  <download>
    <filename value="/entitlement/fwis.xml.sha512" />
    <destination value="C:\Ahsan_Test\fwis.xml.sha512" />
    <result success="true" />
  </download>
</session>

 _with2.WriteLine("option batch abort");
            _with2.WriteLine("option confirm on");

            //Open the session.
            _with2.WriteLine(" open " + comboProtocol.Text.Trim() + "://" + txtUsername.Text.Trim() + "@" + txtHostname.Text.Trim() + ":" + int.Parse(txtPort.Text.Trim()) + " -privatekey=\"" + txtPulicKeyFile.Text.Trim() + "\"");
            _with2.WriteLine("cd " + txtRemoteDir.Text);
            
            //set Transfer mode ASCII to Binary
            _with2.Write("option transfer binary");
            
            //Download the file and hash data file 
            _with2.WriteLine("get \"" + txtDownloadFile.Text + "\" \"" + txtLocalDir.Text + "\"");
            _with2.WriteLine("get \"" + txtDownloadFile.Text + ".sha512\" \"" + txtLocalDir.Text + "\"");
            _with2.Close();