When we generate PDF file error showing (htmlparser.parse(sr) ) in asp.net c#

hii,

when we generate pdf file its working fine on local system but not working on window server showing error (htmlparser.parse(sr) )

code is below

               StringWriter sw = new StringWriter();
                HtmlTextWriter hw = new HtmlTextWriter(sw);               
                pnlPerson.Visible = true;
               pnlPerson.RenderControl(hw);

                StringReader sr = new StringReader(sw.ToString().Replace("<hr>", "<br>"));
                 Document pdfDoc = new Document(PageSize.A3.Rotate(), 10f, 10f, 100f, 10f);
                 iTextSharp.text.html.simpleparser.HTMLWorker htmlparser = new iTextSharp.text.html.simpleparser.HTMLWorker(pdfDoc);              
                PdfWriter.GetInstance(pdfDoc, new FileStream(Server.MapPath("~/") + "PDFFolder/" + tmpId + "test.pdf", FileMode.Create));               
                string ss = Server.MapPath("~/") + "PDFFolder\\" + tmpId + "test.pdf";               
                path = ss;              

                pdfDoc.Open();          
               
                htmlparser.Parse(sr); (Error coming on this line)
                pdfDoc.Close();

please help its urgent

Thanks in advance