Hey Marc,
How many files are you dealing with?
It may be worth your while to spend money on a conversion utility like Batch Docx Converter.
I haven’t used this critter, but if I was dealing with hundreds or thousands of files I’d happily pay the 20 bucks if it worked well.
As for @ALYB’s suggestion – it’s definitely viable – see this thread:
Solved: Options in automating batch conversion of Word.doc to PDFs
Give us some more information about your needs, so we can more appropriately discern how to help you.
-Chris