Adobe PDF – After Converting to PDF

I converted a book of about 500 pages from ADOBE Pagemaker 6.5 / 7…To PDF with Adobe DISTILLER.
Everything went fine thanks to God !
EXCEPT:-

The Heading UNDERLINES are Not coming !
Not a single UNDERLINE on the HEADING or in the paragraphs are showing !

What can be the reason ?

Please do share me with your answers, I need it very urgently !
Thanks