I've suddenly started seeing this error & fear it is related to my upgrade to Adobe Acrobat Pro 9. In my personal life, my father suddenly couldn't open a PDF I made & I thought maybe he had such an old reader, it couldn't handle a newer PDF. Today, however, I received word that an fellow employee is getting this error when she tries to open a PDF that I created since upgrading here at work. My team publishes hundreds of specifications a year in PDF format... with absolutely NO control over what readers customers might use. If Adobe 9 can't create a universally read-able PDF, I need to know if I should downgrade or if there is some other solution. Note: the PDF in personal life was not secured... the PDF in question at work is locked with a password (but only for editing or copying, never been a READ / open problem before).
Thanks for any advice.