/edit: ok I am beginning to figure it out. I went and checked out my mainfile.php for my local site's xoops. I checked the database details in there, and wtf! That db doesn't exist! So then I renamed that mainfile.php to mainfile.php-test and tried to access my backup site. ERROR! Can't find all sorts of things.
So it looks like MY problem is to do with virtual hosts on that box. All along I have been loading the default site in htdocs, instead of the site in my backup folder.
Well, since I didn't have a db to feed the htdocs installation of xoops, I just copied my backup site's files over that. Load up my default site and BINGO! -- there's my backup! Yay!