You mean you need a copy of your forum threads/posts? I see two solution one is to use a bot to scrape the archive (
http://www.yourforum.com/archive/index.php/) the second one would be writing some simple script to dump posts fields in a threaded way directly for the database. You could also read the whole post table directly from the local database backup if you're convinient with it. Does anyone see a better way?