I have the same problem working in CS6.
What I did was open a new project from zero. Then I put the previous project (the one with the problem) inside the new one. AE showed all the errors but eventually I could open the project, remove all the things AE says wich was with problems and got back to work.
It was kinda troubled, but since I wasn’t even able to open the project, this “solution” has saved me plenty of time.
Hope it helps someone else.