Unable to open PDF file using iTextSharp PdfReader object

See more:

itextsharp

I am trying to generate a PDF file from template file and FDF file.
For Example,
PDF File = Template File + FDF File

The PDF file is generated successfully using template and fdf files and able to open it manually using Acrobat Pdf.

However, I am unable to open the generated pdf file using PdfReader object of iTextSharp.
For Example,
PdfReader obj = new PdfReader(outputFileName);

I get the following error on the above line:
Error: Index was out of range. Must be non-negative and less than the size of the collection.
Parameter name: index

Here is the method and client call to the method.

1) Am I using correct method to generate the PDF file? If not, what is the correct method?
2) Is there any known issue with the PdfReader?

Any help would greatly be appreciated.

public static void GenerateFormWithData(string formFilename, string fdfFileName, string outputFileName)
        {
            File.Copy(formFilename, outputFileName, true);

            using (FileStream outputStream = new FileStream(outputFileName, FileMode.Open))
            {
                FdfReader fdfReader = new FdfReader(fdfFileName);
                PdfReader formReader = new PdfReader(fdfReader.FileSpec);
                using (PdfStamper pdfStamper = new PdfStamper(formReader, outputStream))
                {
                    AcroFields pdfForm = pdfStamper.AcroFields;

                    pdfForm.SetFields(fdfReader);
                    pdfStamper.FormFlattening = true;
                    pdfStamper.Writer.CloseStream = false;

                    pdfStamper.Close();
                    outputStream.Close();
                }
                fdfReader.Close();
                formReader.Close();
            }
	PdfReader obj = new PdfReader(outputFileName); // ERROR on this line
            // Note: I am able to open the outputFileName when I double click on the file in Windows Explorer. But not able to read the file using PdfReader after generating it.

        }


            // Client Call
            string formFile = Path.Combine(defaultPath, "MyTemplate.pdf");
            string fdfFile = Path.Combine(defaultPath, "FormDataFile.fdf");
            string outFile = Path.Combine(defaultPath, "MyOutput.pdf");
            PdfLibrary.GenerateFormWithData(formFile, fdfFile, outFile);