PDFCreator.exe testing

I have PDFCreator 2.0.1's source code. I am trying to modify and test the code. I want to send live print jobs to my modifications for testing purposes, I replaced my computer's Program Files > PDFCreator.exe with my modified PDFCreator.exe.  The new PDFCreator.exe crashes every time I send it a print job. Does PDFCreator.exe have to be digitally signed for it work? 

I only modified some GUI text to see if my changes are reflected on a live system.