Reading File Error: illegal characters in path in ASP.Net

Hi

i had asked a question Highlight and focus selected word in IFRAME using jQuery in ASP.Net

It doesnt work all the time. Please help.

        public void getbookmark()
        {
            SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["connString"].ConnectionString);
            string bmnId = Session["bmId"].ToString();
            string bstxt = Session["bookmark"].ToString();

            SqlCommand cmd = new SqlCommand("select bn.vcFilePath from tblBookNodes bn inner join tbl_bookmarks bk on bn.iModuleId=bk.iNodeId where bn.iModuleId='" + bmnId + "' ", conn);
            conn.Open();
            SqlDataReader dr = cmd.ExecuteReader();
            if (dr.Read())
            {
                bytes = (byte[])dr["vcFilePath"];
                conn.Close();
            }
            getfile();
        }
        public void getfile()
        {
            string bmnId = Session["bookmark"].ToString();
            string bstxt = Session["bookmarktxt"].ToString();
            string fileName = bmnId.Replace(" ", "_") + ".htm";
            //string returnpath = "File/htmlFile/";
            string strPath = Server.MapPath("~/htmlFile/");
            
            if (!Directory.Exists(strPath))
            {
                Directory.CreateDirectory(strPath);
            }
            string path = strPath + fileName;
            var doc = new HtmlDocument();
            string html = Encoding.UTF8.GetString(bytes);
            doc.LoadHtml(html);
            StringWriter sw = new StringWriter();
            var hw = new HtmlTextWriter(sw);
            StreamWriter sWriter = new StreamWriter(path);
            sWriter.Write(sw.ToString());
            doc.Save(sWriter);
            sWriter.Close();
            string fileContents = html;
            string searchText = HttpUtility.HtmlEncode(bstxt);
            string newBookmarktag =" <a= '"+bstxt+"'</a>";
            html = html.Replace(bstxt, newBookmarktag);
            //fileContents = fileContents.Replace(elstext, newBookmarktag);
            hfHTML.Value = System.IO.File.ReadAllText(path);
            System.IO.File.WriteAllText(path, hfHTML.Value);
            //Page page = (Page)HttpContext.Current.Handler;
            //MultiView control = ((Cyient_IETM.select)(page)).MultiView1;
            //View View1 = (View)control.FindControl("View1");
            //HtmlControl ctrl = (HtmlControl)View1.FindControl("frmDisplay");
            frmDisplay.Attributes.Add("src", HttpContext.Current.Request.Url + "/.." + "\\htmlFile\\" + fileName);
            //MultiView1.SetActiveView(View1);
        }

newbookmark works fine. I can't use mouse hover on it. If i pass that html to hfHTML it gives error like illegal charecters .

string path = strPath + fileName;
hfHTML.Value = File.ReadAllText(path);

I do get the html file in the path but i am  not able to hover the text.

Update : When write 1st and then read i am able to hover the text but it will not jump to the word. but If i read HTML file it gives error like illegal charecters in path.

System.IO.File.WriteAllText(path, html);
hfHTML.Value = File.ReadAllText(path);