I have just noticed  that there are many blocks of code like this:

           int pageID = 0;
           if (HttpContext.Current.Request.Params["pageid"] != null)
            {
                if (HttpContext.Current.Request.Params["pageid"] != string.Empty)
                {
                    try
                    {
                        pageID = Int32.Parse(HttpContext.Current.Request.Params["pageid"]);
                    }
                    catch { }
                }
            }

Why not use the special functions in this case:

            int pageID = 0;
            if (!string.IsNullOrEmpty(HttpContext.Current.Request.Params["pageid"]))
            {
                Int32.TryParse(HttpContext.Current.Request.Params["pageid"], out pageID);
            }

or just

            int pageID;
            Int32.TryParse(HttpContext.Current.Request.Params["pageid"], out pageID);

?