Apparently the developer(s) of this wonderful add-on have moved on to other things and aren't maintaining it. Fortunately some folks have taken the time to dig into the code and make it work with the new patch. If you're comfortable with manually updating your add-ons, download PetJournalEnhancedWoD.zip from this link ...http://wow.curseforge.com/addons/pet-journal-enhanced/tickets/102-errors-in-wod-beta/
There are a few things that work differently but it's still so far superior to what Blizz gives us.
Also check out the comments on the Curse entry for PetJournalEnhanced, has an additional nicety if you want to patch a few lines of LUA code.