Have you tried right clicking on the PDF and selecting Open With>Choose Default Program and then select your Acrobat program and be sure the always use box is checked? It may be that the open link broke with the update.
You may want to turn off auto-updates or change the options in the Acrobat Preferences under Edit.
Do change the update level, you might succeed with trying to install the previous update, but I doubt it. The other way is to deactivate, uninstall, and reinstall (a lot of work, particularly if the opening suggestion fixes your problem).
