I completed the quests Awakening and Bloodline. During Bloodline, I refused to become a Vampire Lord because I was already a werewolf and wanted to stay as one.

At the end of the (finished) Bloodline quest description, it says "Now I should return to Isran and tell him what happened." But I can't. Every time I talk to Isran, my only options are "I need training in Heavy Armor.", "Any advice for a new vampire hunter?", "What is this place?" and "What's the Dawnguard?"

None of those options advance the quest and no matter how many times I talk to him, he gives me no new quest. How I do I get the quest that follows Bloodline?