Cannot do myself there because phpmyadmin doesn't allow more than 2048 KB files.
You need to change that, forums only get bigger so you need server to server transfer, we host over 100 domains, the main one is about 30gb, aint no way we can down and up all that, think last time we changed states we had 15 minutes downtime, ie back up on the first server for protection against corruption and transfer and everything else, downtime 15 minutes. 100mb to 100mb is pretty quick, think we mirrored the site from the old server initially to get the dns correct with the database running from the new server, ie same urls, not different urls.