Very short “I Fixed It” for today. A client of mine moved a Concrete 5 site to his new IIS server, and all PDF files stopped working. He spent several day siwth his web host troubleshooting the issue, and finally asked me to take a look. It turns out that the php configuration zlib.output_compression needs to be set to Off.
Setting this in the PHP.ini file, I was able to get IE and Firefox browsers working, but webkit (Chrome and Safari) still failed to work. I put the line ini_set(‘zlib.output_compression’,’Off’); in the index.php file of the site, and problem solved!
I am at a loss as to why this was actually happening, but everyone is now happy!