In my last post I described a problem that recently posted PDF files couldn't be opened on Apple iPads and iPhones.  After much work I came across a way of creating the PDFs that avoids the problem.  I'm still not sure what was going wrong, and I think it only affected the CENCO catalog files that I created and posted in the last week.  I have rescanned the CENCO catalogs and uploaded them again to the website.  They can now be downloaded, at least on my iPad and iPhone.  There was never a problem downloading the catalogs on a Windows computer or Mac.