Use a real browser. IE works just fine.
IE is far inferior than Firefox for many reasons, but to each his own.
In what universe is IE considered a viable and properly functioning browser? I've been a Windows server engineer since the NT4 days, and you'd be hard-pressed to find a single engineer, admin, or developer who supports or programs to IE standards. IE is far and away the worst browser on the market, and the only reason it has any market share is that it's packaged as the default browser for Windows.
To the OP's post: there are numerous documented issues with Adobe products and Firefox over version 21.0. Adobe has to get their crap in line to make it function properly with Firefox's isolated kernel. Given the known security issues with many Adobe web products, I would just download the document you want to read and open it on your local machine instead of messing with the in-browser API.