add text stamp crashing program getting error program stopped working

Hi team I have a requirement to run PDF add text stamp as a separate exe so that it will run in the back ground when called. I am running it as a win form with the form deleted. My project has a reference to Aspose.Pdf.dll. When the exe is called it crashes with the message program stopped working. I've determined that it is something in the code that I am using to add the text stamp. when I comment the code out it works. I've attached the code file. Please tell me what I am doing wrong.
Thanks.
Bill