We have a web application that allows user to download PDFs, make annotations in Reader and submit the annotations back for processing. The Servlet that processes the annotations returns a PDF letting the user know if the annotations were processed successfully. Most of the time this works fine. However, we have one group of users that have recently upgraded to Windows XP and IE 7. Suddenly Reader no longer displays the response PDF. We have verified that it still works with IE 6. I have heard reports that the same problem is happening with Firefox.