Ugh, suggest rebooting the game and restarting it. If that doesn't work reboot the device and restart. And beyond that head to
http://contact.bscotch.net and chose the "something is DEFINITELY broken" option and submit a bug report for them to look at. Chances are you're just missing something but I couldn't tell you what, sounds like you've looked everywhere if you're completed the other games (though technically FR and RR have no end so... I call shenanigans on that one!), it's probably just a matter of something not registering to kick off the quest, so bug report it and someone will check it out when they can.