I had this same issue this morning on one of my sites running WP 2.8
After monkeying around with uninstalling and a manual install, I debated whether to try to dig up the All In One SEO v1.6.11 but figured it wasn’t worth it. Instead, I took a backup of the site, did a auto-upgrade to WP 3.0 and then reinstalled All In One SEO v.1.6.12 which solved the issue. My site theme is pretty clean code, so I wasn’t too worried but unfortunately, my approach wasn’t without a few glitches;
1. Auto upgrade to WP 3.0 threw a memory limit error
2. To correct the error, I changed the PHP setting from 32M to to 64M using GDPress Lite plugin.
The memory limit is a bit of a risk because the site is sitting on a shared host, so I’ll just keep an eye on performance. webpagetest.org is a nice little tool if you haven’t used it.
*sigh* Love WordPress but these types of situations are just irritating.
Hope y’al get things fixed up.
