Clicking on a pdf file link in Firefox causes the file to download rather than opening.
I've tried checking and unchecking the "open in browser" box in Reader without success.
In looking at the Applications list in FIrefox Tools>Options>Applications, there is no listing for Adobe Acrobat Document, and I can' t find a way to add that Application. There are two entries for Adobe Acrobat Forms Document and one for Adobe Acrobat XML Data Package. Changing the Action for them doesn't resolve the problem.
Looking at the Control Panel, there is only one instance of Acrobat Reader, that being 9.4.0. I've also tried using the Repair option in Reader.