Awakening of Evil

When approaching one of the human castles, I have to go through the garrison; I stop about 5 steps before the garrison, and I can't go any further. I can approach the second castle, and there's a blue hero standing on the street; an icon appears (indicating that I can attack), but I can't actually attack. My quests haven't been reset; some of them still remain incomplete, without a checkmark or an "X." Could it be because I wandered around a human city in the middle of the game, and I have quests to gain reputation with both the Orcs and the Humans?