at Telerik.Windows.Documents.Utilities.Guard.ThrowExceptionIfTrue(Boolean condition, String message)
   at Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.Model.Types.IndirectObject.get_Content()
   at Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.Export.PdfExportContext.BeginExportIndirectObject(IndirectObject indirectObject, Int64 offset)
   at Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.Model.Types.IndirectObject.Write(PdfWriter writer, IPdfExportContext context)
   at Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.Export.PdfExporter.WritePendingIndirectObjects(IPdfExportContext context, PdfWriter writer)
   at Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.Export.PdfExporter.WriteFontsFromContext(PdfWriter writer, IPdfExportContext context)
   at Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.Export.PdfExporter.Export(IRadFixedDocumentExportContext context, Stream output)
   at Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.PdfFormatProvider.<>c__DisplayClass21_0.<ExportOverride>b__0()
   at Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.ExceptionHandling.ExecutionHandler.TryHandleExecution[E](Action operation)
   at Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.PdfFormatProvider.ExportOverride(RadFixedDocument document, Stream output, CancellationToken cancellationToken)
   at Telerik.Windows.Documents.Common.FormatProviders.FormatProviderBase`1.Export(T document, Stream output, Nullable`1 timeout)