Telerik Pdf Processing Cannot open the attached pdf file and exception occur.

How do i slove it?

Code :
  RadFixedDocument document = new PdfFormatProvider().Import(input);

Exception Message :
   System.UriFormatException  無效的 URI: 無法剖析主機名稱。

Source :
   Telerik.Windows.Documents.Fixed

Stack Trace :

於 System.Uri.CreateThis(String uri, Boolean dontEscape, UriKind uriKind)
   於 System.Uri..ctor(String uriString, UriKind uriKind)
   於 Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.Model.Elements.Actions.UriActionObject.ToAction(PostScriptReader reader, IRadFixedDocumentImportContext context)
   於 Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.Model.Elements.Annotations.LinkObject.ToAnnotationOverride(PostScriptReader reader, IRadFixedDocumentImportContext context)
   於 Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.Model.Elements.Annotations.AnnotationObject.ToAnnotation(PostScriptReader reader, IRadFixedDocumentImportContext context, Double pageHeightInDip)
   於 Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.Model.Elements.DocumentStructure.Page.CopyPropertiesTo(PostScriptReader reader, IRadFixedDocumentImportContext context, RadFixedPage fixedPage)
   於 Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.Model.Elements.DocumentStructure.DocumentCatalog.CopyPagePropertiesTo(PostScriptReader reader, IRadFixedDocumentImportContext context)
   於 Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.Model.Elements.DocumentStructure.DocumentCatalog.CopyPropertiesTo(PostScriptReader reader, IRadFixedDocumentImportContext context)
   於 Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.Import.RadFixedDocumentImportContext.BeginImportOverride()
   於 Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.Import.BaseImportContext.BeginImport(Stream pdfFileStream)
   於 Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.Import.PdfImporter.Import(Stream input, IPdfImportContext context)
   於 Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.PdfFormatProvider.ImportOverride(Stream input)
   於 Telerik.Windows.Documents.Common.FormatProviders.FormatProviderBase`1.Import(Stream input)
   於 Telerik.Windows.Documents.Common.FormatProviders.BinaryFormatProviderBase`1.Import(Byte[] input)