Having a similar problem. I am trying Montreal to Dublin or Toronto to Dublin, so far I have tried one-way, round, and multicity and each time I get the same error message. Also noticed that it does not allow me to click search partner airlines, after entering the destination the search partner option disappears and there's a message saying "This Itinerary can only be booked as a Classic Award. To continue click Search Flights" and when I click continue, I get the same error. Tried various dates, doesn't make a difference. But if I change my departure point to any american city, i don't have the same problem