file download working in firefox and IE is not working in google chrome (chrome downloading default.aspx instead of actual file)

Hi following is the code which i have used to download the uploaded file.

 private void DownloadFile(object sender)
    {
        LinkButton lnkBut = (LinkButton)sender;
        string fileName = lnkBut.Attributes["fileName"];
        String filePath = Server.MapPath("~/FilesUploaded/") + fileName;

        FileWebRequest objRequest = (FileWebRequest)WebRequest.Create(filePath);
        FileWebResponse objResponse = (FileWebResponse)objRequest.GetResponse();
        int bufferSize = 1;
        Response.Clear();
        Response.ClearHeaders();
        Response.ClearContent();
        Response.AppendHeader("Content-Disposition:", "attachment; filename=" + lnkBut.Text);
        Response.AppendHeader("Content-Length", objResponse.ContentLength.ToString());
        Response.ContentType = this.ResponseContentType(fileName);  // the method supplies the contenttype based on file extention
        byte[] byteBuffer = new byte[bufferSize + 1];
        MemoryStream memStrm = new MemoryStream(byteBuffer, true);
        Stream strm = objRequest.GetResponse().GetResponseStream();
        byte[] bytes = new byte[bufferSize + 1];
        while (strm.Read(byteBuffer, 0, byteBuffer.Length) > 0)
        {
            Response.BinaryWrite(memStrm.ToArray());
            Response.Flush();
        }
        Response.Close();
        Response.End();
        memStrm.Close();
        memStrm.Dispose();
        strm.Dispose();
    }


The above method works fine with the firefox and IE , i am able to download all types of files like zip,txt,xls,xlsx,doc,docx

but when i download the same file from googlechrome , instead of actual zip file, the default.aspx page has been downloaed

Please any one tell me what is the way to get the actual file in google chrome.