Please try the following
string FileName = "test.rpt";
string FullPath = Path.Combine("ReportFolder", FileName);
rptDoc.Load(Server.MapPath(FullPath));
rptDoc.SetDataSource(dt);
ExportOptions CrExportOptions;
DiskFileDestinationOptions CrDiskFileDestinationOptions = new DiskFileDestinationOptions();
PdfRtfWordFormatOptions CrFormatTypeOptions = new PdfRtfWordFormatOptions();
CrDiskFileDestinationOptions.DiskFileName = "D:/GeneratedPDF/PDFFileName.pdf";
CrExportOptions = rptDoc.ExportOptions;
CrExportOptions.ExportDestinationType = ExportDestinationType.DiskFile;
CrExportOptions.ExportFormatType = ExportFormatType.PortableDocFormat;
CrExportOptions.DestinationOptions = CrDiskFileDestinationOptions;
CrExportOptions.FormatOptions = CrFormatTypeOptions;
rptDoc.Export(CrExportOptions);
Thanks,:rose::thumbsup:
Imdadhusen