Well, this sucks. I just ran into a game-breaking glitch in Assassin’s Creed: Brotherhood.
It was the beginning of sequence 3, and the game told me I had email to check outside of the Animus. After I checked my email, I quit out of the game to write my early impressions. When I came back to the game, it refused to let me hop into the Animus to go back to Rome. Instead, it would either send me back into the lab or warp me to somewhere random in the villa for a minute, then warp me back to the cave. Without the ability to go to Rome, I can’t actually proceed through the game.
(NOVEMBER 21, 2010 UPDATE: I added this video showing exactly the glitch I experienced)
I’m not the only one with this problem. Knowing that gives me hope that Ubisoft will fix this soon. For now though, I’m left with a useless copy of Assassin’s Creed: Brotherhood.
I have an extremely low tolerance for game-breaking glitches, so unless Ubisoft fixes this quick,
In Third Person 
You should try talking to each of your team members then going back on the chair. I spoke to them first then went to check my email. After each conversation, it auto-saved, maybe that will work?
Thank you for the advice. I have tried that though, and nothing works.
http://www.youtube.com/watch?v=e25pqjjch6Y
This is a video of exactly what’s happened to me. Until the game is patched, my only course of action is to restart and hope for the best.
Bad luck, hopefully they’ll bring out a patch soon.