Editting TimeSheets with the PSI QueueUpdateTimesheet

Would some one who has been successful with editting TimeSheets via QueueUpdateTimesheet() help us out with a look at this code? 

Variables:

DateTime [] dates; // arrays are same size
decimal [] actuals;
Guid tsLineGuid;   // from existing TimeSheet

try
{
   SvcAdmin.TimesheetLineClassDataSet tsLineClassDs =
      adminClient.ReadLineClasses(SvcAdmin.LineClassType.AllNonProject, SvcAdmin.LineClassState.Enabled);


   // delta TS is the difference in previous to new timesheet
   SvcTimeSheet.TimesheetDataSet deltaTsDs = new SvcTimeSheet.TimesheetDataSet();
   SvcTimeSheet.TimesheetDataSet.HeadersRow headersRow = deltaTsDs.Headers.NewHeadersRow();
   headersRow.RES_UID = resourceGuid;
   headersRow.TS_UID = timeSheetGuid;
   headersRow.WPRD_UID = periodGuid;
   headersRow.TS_CREATOR_RES_UID = managerGuid;
   headersRow.TS_NAME = "Delta Timesheet " + periodStartDate + " to " + periodFinishDate;
   headersRow.TS_COMMENTS = "Delta Timesheet created by Web Part.";
   headersRow.TS_ENTRY_MODE_ENUM = (byte)PSLibrary.TimesheetEnum.EntryMode.Daily;
   deltaTsDs.Headers.AddHeadersRow(headersRow);


   SvcTimeSheet.TimesheetDataSet.LinesRow line = deltaTsDs.Lines.NewLinesRow();
   line.TS_UID = timeSheetGuid;
   line.TS_LINE_UID = tsLineGuid;
   line.TS_LINE_CLASS_UID = tsLineClassDs.LineClasses[0].TS_LINE_CLASS_UID;
   line.TS_LINE_COMMENT = "Timesheet created by Web Part.";
   line.TS_LINE_STATUS = (byte)PSLibrary.TimesheetEnum.LineStatus.NotApplicable;
   line.TS_LINE_VALIDATION_TYPE = (byte)PSLibrary.TimesheetEnum.ValidationType.Unverified;
   line.TS_LINE_CACHED_ASSIGN_NAME = tsLineClassDs.LineClasses[0].TS_LINE_CLASS_DESC;
   deltaTsDs.Lines.AddLinesRow(line);


   // add actuals
   for (int i = 0; i < dates.Length; i++)
   {
      SvcTimeSheet.TimesheetDataSet.ActualsRow actual = deltaTsDs.Actuals.NewActualsRow();
      actual.TS_LINE_UID = tsLineGuid;
      actual.TS_ACT_VALUE = actuals[i];
      actual.TS_ACT_START_DATE = dates[i];
      actual.TS_ACT_FINISH_DATE = dates[i];
      deltaTsDs.Actuals.AddActualsRow(actual);
   }


   timeSheetClient.PrepareTimesheetLine(timeSheetGuid, ref deltaTsDs, new Guid[] { tsLineGuid });
   timeSheetClient.QueueUpdateTimesheet(timeSheetGuid, jobGuid, deltaTsDs);


}
catch (SoapException ex)
{
   throw new Exception(ex.Message);
}
catch (WebException ex)
{
   throw new Exception(ex.Message);
}
catch (Exception ex)
{
   throw new Exception(ex.Message);
}

The error is coming via a GridView Editing Javascript window:

Message: Sys.WebForms.PageRequestManagerServerErrorException: ProjectServerError(s) LastError=GeneralItemDoesNotExist Instructions: Pass this into PSClientError constructor to access all error information
Line: 4723
Char: 21
Code: 0
URI: http://<my_url>/ScriptResource.axd?d=...

The goal is to take delta hours and update an existing TimeSheet with them.  I tried using the tsLineGuid and timeSheetGuid from the existing TimeSheet and I tried creating them anew with Guid.NewGuid(); 

---

Jonathan M Beck