When you are running Classic, you have switched to the Adobe printer in the Chooser, and you try to File/Export a Pagemaker document to PDF, Pagemaker works for a few seconds, and then opens Acrobat Distiller. Distiller then works for a few seconds, but then stops with an error message.
To work around this, click the Pause button which shows in Distiller as soon as it opens. In the same folder with your original file (which, of course, should be a copy of your real original), you will find a temporary file called myfile.ps. Now open this PostScript file with Preview, and Preview will automatically convert it to a PDF. Save it now and unpause Distiller. The PostScript file disappears, but you are left with the PDF.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20060330133446978