How do I talk to Jaufree when I'm delivering the Amulet to him? I've pressed every key, and I can't talk to him.
Oblivion is horrendously broken. It's probably bugged. If you are on PC you should probably download the Unofficial Patches. Though that probably won't fix your current issue. If you've already tried reloading a previous save, you might need to use the console to fix your issue, but I wouldn't begin to know what commands to use.
Is this at the beginning of the game, at Weynon Priory? If you're on pc, you can use the console command setstage MQ02 50 to advance the quest step to one where you have already talked to him. Not sure what to do if you're on a console, though.