Adobe component Filter/FOPN_intrlnk

Hello,
I have a handfull of PDF's I'm trying to view with Adobe Acrobat Pro v. 6.0.1 (on WinXP pro). When I try to open them Adobe tells me its checking for updates followed by a message telling me there is a missing component "Filter/FOPN_intrlnk". I've scoured the net for this component/plug-in but can't seem to find it. I've tried using the Adobe 7 beta version to open them, but get the same messages. Can anyone suggest a way around this? By the way, the originator of the PDF's claims they are password protected, but I never get to the password prompt.

Thanks for any suggestions.