The old B2 hacks are causing havoc with my upgrade to WordPress. I removed everything in the root of my website and opened WordPress and connected to my previous mysql database. When I setup the new b2config.php I used the old one extensively to help fill out the new one. Your post helped me realize an old hack I had applied that changed the name of my $blogfilename = ‘index.php’; line to $blogfilename = ‘archive’;.
This broke the archives. I’ve changed it back and all is good. I’m just posting in case someone else upgrades and has done the same thing. Hopefully they’ll find this post.