Error export HTML

Question

hello i have an erreor in my program:
MemoryStream oStream;
MemoryStream oStream;
            CrystalReport1 crt = new CrystalReport1();
            string customerFilePath = Server.MapPath("
DsActAction.xml");
            DataSet ds = new DataSet();
            ds.ReadXml(customerFilePath);
            crt.SetDataSource(ds);
            DiskFileDestinationOptions diskOpts = ExportOptions.CreateDiskFileDestinationOptions();
            ExportOptions exportOptions = new ExportOptions();
            exportOptions.ExportFormatType = ExportFormatType.HTML40;
            exportOptions.ExportDestinationType = ExportDestinationType.DiskFile;
            diskOpts.DiskFileName = "D:
test.html";
            exportOptions.ExportDestinationOptions = diskOpts;
            crt.Export(exportOptions);
            Response.ClearContent();
            Response.ClearHeaders();
            Response.ContentType = "text/html";
the error is at : crt.Export(exportOptions);
the reference of object is not define as un instance of object !
please help me.
thanks a lot:

Answer 1

The same error, i should be my error, exportpath i did ditination of my file so is correct as it is :
CrystalReport1 crt = new CrystalReport1();
            string customerFilePath = Server.MapPath("
File.xml");
            DataSet ds = new DataSet();
            ds.ReadXml(customerFilePath);
            crt.SetDataSource(ds);
            DiskFileDestinationOptions diskFileDestinationOptions;
            ExportOptions exportOptions = new ExportOptions();
            diskFileDestinationOptions = new DiskFileDestinationOptions();
            exportOptions = crt.ExportOptions;
            exportOptions.ExportDestinationType = ExportDestinationType.DiskFile;
            exportOptions.FormatOptions = null;
            exportOptions.ExportFormatType = ExportFormatType.HTML40;
            HTMLFormatOptions html40FormatOptions = new HTMLFormatOptions();
            html40FormatOptions.HTMLBaseFolderName = "
d:\a.html" + "Html40Folder";
            html40FormatOptions.HTMLEnableSeparatedPages = true;
            html40FormatOptions.HTMLHasPageNavigator = true;
            html40FormatOptions.FirstPageNumber = 1;
            html40FormatOptions.LastPageNumber = 3;
            exportOptions.FormatOptions = html40FormatOptions;
            crt.Export(exportOptions);
please help me and thenk you a lot.