Have the same question, but trying to convert from 9 to 7. Of course, not sure if that will solve my problem since I'm on Windows7 now. My temporary workaround is that I have someone who is still using XP and acrobat 7 pro open the pdf and print it to a new file name, then I'm able to use it in one of my legacy applications that can read version 7 pdf but not version 9 pdf.