Seems like this has been a common issue discussed in the forums, but I haven't seen anything that states it's a known bug or if there is a workaround. Our team has Acrobat 8 (most should have upgraded to 8.1.2), and some of our reviewers have upgraded to Acrobat Reader 9. It seems they aren't able to comment on PDFs even though we've enabled them for commenting. Anyone have information about this issue?
I only have Reader and not Acrobat so there is much of the "lingo" I can't be sure if I understand
but you could check if this thread has anything to do with your situation :
(There is an extreme bunch of issues between Acrobat 8 Pro and Reader 9 dating back to 2008)