Modified date changes when just opening PM file

Question

We use modified dates frequently at my business. We have lots of things that reoccur only once a year, and we'd like to keep the file dates listed as such in the folder views.
All the sudden, however, Pagemaker files have started updating the modified date to the moment you touch the file, even if you make no changes. If you open it, it now becomes today's date & current time.  It's really messing up our method of doing things.
It's not happening with any of our CS4 files, or any Microsoft Office files. Also, it's only happening on files stored on the server. It doesn't happen when we do a test of saving a Pagemaker file locally. The problem is, we don't store anything locally. Everything is stored on the server so everyone can access the file and so it's backed up.
We have a Windows based computer environment but an Apple server with OS 10.3.8 (Tiger--- yeah, I know, old, but it's as far as we can update that server at this time and are looking at getting a new one sometime, but it might be a year or so.) 
The "modified date" problem has taken place only in the past 2 weeks. We have not done anything significant for changes or updates for quite a while on either the local computer or server ends. We restarted the server recently just to refresh things, and also added another user to the server and set some permissions for that user in the past 2 weeks.
What could be causing this all of the sudden, and how can it be fixed?

Answer 1

Acrobat 9 makes PDF versions 4.0 and higher. You need a PDF version 5.0 to handle transparencies well. PDF version 4.0 doesn't handle transparency effects well at all.
Pagemaker needs Acrobat 5 to be able to directly export PDF's with custom job settings. It only generates a PDF version 4.0, but works for our needs in Pagemaker.
I choose to keep both Distiller versions to make our work easier. When you have 20 ads open in Pagemaker, and you send the first one as a postscript through the print window, it sets up the "File, Export" in Pagemaker to use the correct PDF job setting, and then you can just do "File, Export to PDF" for the next 19 ads and it makes perfect PDF's. Works slick instead of having to make postscripts of all 20 ads first and then run them through Distiller. If you only have Distiller 9 installed, it doesn't let you select any custom job settings from your Distiller. Crazy, I know, but that's what I've figured out we have to do to get it to work. Have to have Distiller 5.0 to control PDF settings in Pagemaker and still be able to export from the file menu directly to PDF.
Distiller 9 is used for all other more advanced design pieces created in InDesign or Photoshop that are saved as a postscript first and PDF's are made the long way in those cases (running postscript through Distiller 9 at the end).