Happened to me last week booking an award flight.

I got the same error message at the very end.

I called, was on hold, so tried again and it went through before anyone picked up.

Then ALL the previous bookings went through as well - so I had 4 award flights showing under MY Trips for the same flight.

I canceled all but the last one that I got the email confirmation on but it would not let me choose seats. Said I had to wait 24 hours - odd as this never happened before.

I called the DM desk the next day as I had the same issue with selecting seats. I can't remember exactly terminology, but basically the flight was being held (I had the confirmation #and all) but the tickets were not issued.

The rep was able to fix it over the phone, said they have been having LOTS of award ticketing issues.