Hi, I'm trying to add a new item to a sharepoint list from a winform application in c# using web services. As only result, I'm getting the useless exception "Exception of type 'Microsoft.SharePoint.SoapServer.SoapServerException' was thrown."

I have a web reference named WebSrvRef to http://server/site/subsite/_vti_bin/Lists.asmx

And this code:

        XmlDocument xmlDoc;
        XmlElement elBatch;
        XmlNode ndReturn;
        string[] sValues;
        string sListGUID;
        string sViewGUID;

        if (lstResults.Items.Count < 1)
        {
            MessageBox.Show("Unable to Add To SharePoint\n" +
                "No test file processed. The list is blank.", 
                "Add To SharePoint", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
            return;
        }

        WebSrvRef.Lists listService = new WebSrvRef.Lists();
        sViewGUID = "{xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx}"; // Test List View GUID
        sListGUID = "{xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx}"; // Test List GUID

        listService.Credentials= System.Net.CredentialCache.DefaultCredentials;

        frmAddToSharePoint dlgAddSharePoint = new frmAddToSharePoint();
        if (dlgAddSharePoint.ShowDialog() == DialogResult.Cancel)
        {
            dlgAddSharePoint.Dispose();
            listService.Dispose();
            return;
        }

        sValues = dlgAddSharePoint.Tag.ToString().Split('~');
        dlgAddSharePoint.Dispose();

        string strBatch = "<Method ID='1' Cmd='New'>" +
            "<Field Name='Client#'>" + sValues[0] + "</Field>" +
            "<Field Name='Company'>" + sValues[1] + "</Field>" +
            "<Field Name='Contact Name'>" + sValues[2] + "</Field>" +
            "<Field Name='Phone Number'>" + sValues[3] + "</Field>" +
            "<Field Name='Brand'>" + sValues[4] + "</Field>" +
            "<Field Name='Model'>" + sValues[5] + "</Field>" +
            "<Field Name='DPI'>" + sValues[6] + "</Field>" +
            "<Field Name='Color'>" + sValues[7] + "</Field>" +
            "<Field Name='Compression'>" + sValues[8] + "</Field>" +
            "<Field Name='Value % 1'>" + (((float)lstResults.Groups["Value 1"].Tag)*100).ToString("##0.00") + "</Field>" +
            "<Field Name='Value % 2'>" + (((float)lstResults.Groups["Value 2"].Tag)*100).ToString("##0.00") + "</Field>" +
            "<Field Name='Value % 3'>" + (((float)lstResults.Groups["Value 3"].Tag)*100).ToString("##0.00") + "</Field>" +
            "<Field Name='Value % 4'>" + (((float)lstResults.Groups["Value 4"].Tag)*100).ToString("##0.00") + "</Field>" +
            "<Field Name='Value % 5'>" + (((float)lstResults.Groups["Value 5"].Tag)*100).ToString("##0.00") + "</Field>" +
            "<Field Name='Comments'></Field>" +
            "<Field Name='Overall'>" + (fTotalScore*100).ToString("##0.00") + "</Field>" +
            "<Field Name='Average'>" + (fTotalAvg * 100).ToString("##0.00") + "</Field>" +
            "<Field Name='Transfered'>" + sValues[9] + "</Field>" +
            "<Field Name='Notes'>" + sValues[10] + "</Field>" +
            "<Field Name='Resolved'>" + sValues[11] + "</Field>" +
            "</Method>";

        try
        {
            xmlDoc = new System.Xml.XmlDocument();
            elBatch = xmlDoc.CreateElement("Batch");

            elBatch.SetAttribute("OnError", "Continue");
            elBatch.SetAttribute("ListVersion", "1");
            elBatch.SetAttribute("ViewName", sViewGUID);

            strBatch = strBatch.Replace("&", "&amp;");
            elBatch.InnerXml = strBatch;

            ndReturn = listService.UpdateListItems(sListGUID, elBatch);

            MessageBox.Show(ndReturn.OuterXml);
            listService.Dispose();                
        }
        catch(Exception Ex)
        {
            MessageBox.Show(Ex.Message +
                "\n\nSource\n" + Ex.Source +
                "\n\nTargetSite\n" + Ex.TargetSite +
                "\n\nStackTrace\n" + Ex.StackTrace, 
                "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
            listService.Dispose();
        }

What am I doing wrong? What am I missing? Please help!!

Frank