Mod the DupChecker Program

I have a C# program that currently sends a message when errors are discovered. However, the message aspect isn't working and I want to just comment it out so it doesn't send messages. In it's place I want a file "error.txt" created with the information currently put into the body of the message. The program needs to add to if one exist, or create an error.txt file if one doesn't. The location of the error.txt file needs to be specified and read from the existing "FormDupeChecker.exe.config" file. I don't care how you name it, just so it can be populated in that file and read from there so the "error.txt" file gets created and updated to the correct location.
Attached is an snippet from the program.cs. Full project code to follow after acceptance of project.