Failed to open map file. This is most likely because the map was saved with a newer version of the engine. 4.5.1

WHY? IM ON 4.5.1 PLZ HELP ME, IM ON A CONTEST AND ALL MY WORK HAS BEEN SAVED IN THE SAME ENGINE VERSION!!!

Failed to open map file. This is most likely because the map was saved with a newer!! - General Discussion - Unreal Engine Forums!!&p=171523#post171523