Download pdf document in save as dailog

hi,
 I am using following code for download pdf in save as dialog but there is problem in IE,
anyone can solve my problem

private void DownloadFile(string fname, bool forceDownload)
    {
        string path = MapPath(fname);
        string name = Path.GetFileName(fname);
        string ext = Path.GetExtension(fname);
        string type = "";
        Response.ClearHeaders();
        Response.ClearContent();
        // set known types based on file extension  
        if (ext != null)
        {
            s ...