I've had occasional trouble on other MMOs with particular zones when their files would become corrupted. In these situations, I've had to delete the offending zone file and repatch.
It's never happened to me with CoH though. Everything's packed into piggs, so I wouldn't know where to begin, except reinstalling.
If you reinstall, be sure to backup your database to save all those wonderful characters and their info.
I imagine that it is, but is AP still unreachable in Offline Mode?