I verified that I do have the latest version of FireFox (and EverNote) installed, and the EN Web clipper will still not install properly on FireFox. It reports that it installed correctly, but the EN icon never appears in the FireFox tool bar.
And the link to an EN Support page noted in a post above by gazumped, doesn't get me anywhere. It does get me to an EN page for "Help and Learning" but there is no way to actually contact EN to report a problem.
Methinks perhaps there really isn't any EN tech support any more? Posting messages to the user community may help in some instances, but that is not the same thing at all as company-provided Tech Support, which I believed I was paying for when I upgraded to Premium some time ago. Now they have re-configured all their subscription levels, and I find I am on "Personal" . . . but I can't find a level that offers Tech Support. How can that be?