«Internal Server Error». It's impossible from this side. The best would be if you browse your files through FTP and be sure ALL the files that you need in your site are already there. All the files. Each one, in its place.
Yes. I think so.
Yes, it's a desesperated method. You have to remember to backup all the IMAP directories for the domain/subdomain. I've lost mine ones :rolleyes:. But I think it wasn't a critical lost.