What operating system?
I've had this problem from time to time for four years -- finally figured out a solution.
If you take the PM doc you're trying to PDF out of the folder that it's in and put it on your desktop. Then open it and PDF, it should work. It's been the solution for me. I set the distiller to 'ebook'. that's the only other thing I play with.
I can put the PM doc *back* into the folder it came from and the distiller will fail to produce a postscript file for which it gives me an error message. Take the PM out and put onto the desktop....no problem, it PDFs right away.
Haven't gotten around to creating a new folder and trying to put it in there. Long as it works this easily, I'm fine.