.pmd files

Do you mean, you have some old .pmd files you want to convert to PDF, but don't have PageMaker anymore?

OR

Do you have PageMaker on a computer now, but you cannot successfully export PDFs from it with a current Acrobat/Distiller?

These are two different situations with different answers.

Distiller never did it. PMD files are PageMaker, right? You need PageMaker, 20 years dead, and a computer you can run it on. Also, the discontinued InDesign CS6 can be used. No current Adobe app will read them.

Distiller converts only Postscript files to PDF!