I do ads for a quarterly magazine, and when the book goes to press, all the ads are made into PDF files (from InD3 using Screen settings- Mac OSX). The ads are put on a web server where they can be accessed from an HTML page via link. About 75 ads in every issue.

Before I post the ads, I use Acrobat 6 to batch process all the ads and change the security settings so that changes or extracting artwork or text can't be done. I also set it for low res printing only.

I've been doing it this way for about a year, no problems. Now all of a sudden I'm getting feedback that some people on PCs are getting a "cannot decrypt this file" error message when they try to download an ad from the web site.

Any ideas on why this would happen now?

Thanks to one and all