Unspecified error on report export

Hi,  I am nearly there with my reporting app!  The final piece is to export reports, I have copied code found on the forum to complete this task but I am getting an error:

System.Runtime.InteropServices.COMException was caught

  ErrorCode=-2147467259

  HResult=-2147467259

  Message=Unspecified error

  Source=rptcontrollers.dll

  StackTrace:

       at CrystalDecisions.ReportAppServer.Controllers.ReportSourceClass.Export(ExportOptions pExportOptions, RequestContext pRequestContext)

       at CrystalDecisions.ReportSource.EromReportSourceBase.ExportToStream(ExportRequestContext reqContext)

       at CrystalDecisions.CrystalReports.Engine.FormatEngine.ExportToStream(ExportRequestContext reqContext)

       at CrystalDecisions.CrystalReports.Engine.FormatEngine.Export(ExportRequestContext reqContext)

       at CrystalDecisions.CrystalReports.Engine.FormatEngine.Export()

       at CrystalDecisions.CrystalReports.Engine.ReportDocument.Export()

       at TransLite_Browser.reportHost.TestReport() in C:\temp\TransLite_Browser\TransLite_Browser\reportHost.xaml.vb:line 89

  InnerException:

The code I am using is below and is running in the same function that loads the report:

CyrstalRptsViewer.ViewerCore.ReportSource = cryRpt

  Try

                Dim CrExportOptions As ExportOptions '= cryRpt.ExportOptions

                Dim CrDiskFileDestinationOptions As New  _

                DiskFileDestinationOptions()

                Dim CrFormatTypeOptions As New PdfRtfWordFormatOptions

                CrDiskFileDestinationOptions.DiskFileName = "C:\jobreport.pdf" 'pdfFile

                CrExportOptions = cryRpt.ExportOptions

                With CrExportOptions

                    .ExportDestinationType = ExportDestinationType.DiskFile

                    .ExportFormatType = ExportFormatType.PortableDocFormat

                    .DestinationOptions = CrDiskFileDestinationOptions

                    .FormatOptions = CrFormatTypeOptions

                End With

                cryRpt.Export()

            Catch ex As Exception

                MsgBox("Error exporting report: " & ex.ToString)

            End Try

Why the error is something out of place?