We've never seen this before, neither have FOX announcers Dick Stockton and Charles Davis.
A 3rd and 4 pass to Dolphins WR Davone Bess, right in front of Saints head coach Sean Payton and assistant head coach Joe Vitt, bounced off the turf and was trapped. Somehow, a ref with a great view missed the ball underneath Bess' leg and ruled it complete for an eight yard gain.
Payton challenged the play. Replays clearly showed it was incomplete, and not even close.
After a lengthy delay, the umpire announced that due to a replay malfunction, no replay review was possible. The play was upheld, and the Saints as a compromise were not charged a timeout.
The Saints ended up forcing a punt on the drive, but the extra yardage allowed the Dolphins to pin the Saints inside their own 10.
UPDATE: Late in the second quarter, a fumble by Miami was reviewed and upheld in favor of the Saints. Apparently the replay system was fixed.