C# - Generate PDF With ITextSharp

I am trying to add an image to the top of every page on an existing PDF. I have tried using PdfStamp but for some reason when I try to print the pdf from Chrome all I get is a black page. Also Adobe Reader only shows the original document. Does anyone have any ideas on how to get it working? Here is the code.

public partial class MakePdf : System.Web.UI.Page
{
public MemoryStream m = new MemoryStream();
protected void Page_Load(object sender, EventArgs e)
{
Document document = new Document(PageSize.LETTER);
Response.ContentType = "application/pdf";
string RESULT = @"C:UsersmaitchisonDocumentsPdfService Report Search - 650-10-067 4114.pdf";
PdfReader reader = new PdfReader(RESULT);
PdfStamper stamp = new PdfStamper(reader, m);
try
{
// Set ContentType and create an instance of the Writer.
Response.ContentType = "application/pdf";
PdfWriter writer = PdfWriter.GetInstance(document, m);
writer.CloseStream = false;
// Open Document
document.Open();
int n = reader.NumberOfPages;
int i = 1;
PdfContentByte cb = writer.DirectContent;
PdfContentByte over;
Barcode128 barcode128 = new Barcode128();................