I am having trouble with uploading a file,

I am using Devexpress, When I choose a valid file to upload it says "Object reference not set to an instance of an object." If I put the filepath and into into the database manually and add the file to folder where web.config is set to I can see the file and download it. this is the part of code that breaks when trying

  protected void DocumentUpload_OnFileUploadComplete(object sender, FileUploadCompleteEventArgs e)
       {
           if (!e.UploadedFile.IsValid) return;

           GridViewDetailRowTemplateContainer container = ((Control)sender).NamingContainer as GridViewDetailRowTemplateContainer;
           Int32 index = container.VisibleIndex;

           var orderId = Convert.ToInt32(ViewOrdersGridView.GetRowValues(index, ViewOrdersGridView.KeyFieldName));
           var fileNumber = ViewOrdersGridView.GetRowValues(index, ElsaConstants.FileNumber).ToString();
           var userId = Convert.ToInt32(Session[ElsaConstants.UserId]);
           string directory = ConfigurationManager.AppSettings[ElsaConstants.UploadDirectory];
           if (!Directory.Exists(directory))
           {
               Directory.CreateDirectory(directory);
           }

           string fileType = Path.GetExtension(e.UploadedFile.FileName);
           string fileName = e.UploadedFile.FileName.Replace(fileType, string.Format("_{0}{1}", fileNumber, fileType));
           string resultFilePath = directory + fileName;
           e.UploadedFile.SaveAs(resultFilePath, true);//MapPath

           using (var context = new ELSAEntities())
           {
               var document = new Document
               {
                   OrderId = orderId,
                   DocumentPath = fileName,
                   DateCreated = DateTime.Now,
                   CreatedBy = userId
               };

               context.Document.Add(document);
               context.SaveChanges();
           }
       }<pre><pre><pre lang="c#">