Forum:Main Quest Stopped Working!

I just completed the "Pride Before a Fall" quest, received my quest reward and the quest was moved from current to completed quests. I have verified this with great frustration countless times. However, the Main Quest seems to have derailed. After a few days of time in the game, I had not been prompted by the Main Quest. So I looked at a video online and it appears that I have somehow broken the story line! I spoke to Aldous after witnessing Mercedes' duel, and received my quest reward, at which point Aldous is supposed to be interrupted and the next quest begins. THIS DID NOT HAPPEN! Aldous is just standing around now, with nothing to say when I "speak" to him. I have traveled to the southern waycastle where the next quest is meant to begin, but nothing happens. And I have traveled back to the hill top castle where I last spoke with Mercedes, but it is now completely vacant. What is going on?! Please help. I do not care to start the entire game over. Thanks you!