ErrPtnr is the Error dialog for PDFCreator. PDFSpool.exe does not have the ErrPtnr because it is compiled without a User Intface, so you cant add the Form.
I dont know how to fix this too, but maybe it is enough if you only compile the PDFCreator.exe. Afaik the PDFSpool.exe only starts PDFCreator.exe if it is not running and sends it the Postscript Files that it gets from Redmon. I dont think you have to change a lot here.