It seems that the only program that can reliably generate a PDF document (.pdf) from FDF form source (.fdf) is Adobe Acrobat. As far as we know, fdf to pdf conversion can be achieved through the Import data and Manage form data options in the programs File menu. There is also the possibility of importing .fdf files to other programs, so the PDF can be generated there as well, but this option seems to require Acrobat installed anyway.
It is likely that some programming solutions for web forms exist and can be used for the very same purpose. But for this you should consult sites like stackoverflow or similar websites, more suited for your needs..Open FDF file Open PDF file
Mac version of Adobe's PDF handling software
Free reader for viewing PDF files