The 8.1.3 updater cannot quit Adobe's own programs if running. OK, that's minor. So, I quit the offending program, and the updater runs... only to tell me that the update failed because something in the set-up was modified since the original installation, and that I should reinstall the program and then run the update again. Ahem. After I just freshly reinstalled the whole caboodle, and let it install the browser plug-in and all!

What a colossal waste of time!