What version of the Mac OS are you using? I have 10.4 and if you have this, or anything later (maybe earlier versions as well, I don't know), you do not need any third party software. In whatever program you are printing from (Word, for example), select File->Print. One of the buttons on the print screen that appears is "PDF". Click on this and select "Save as PDF..." Viola! You've got your PDF without needing Acrobat or PrimoPDF or anything else.