I had also noticed that my tags weren't working, so I figured that might be a database issue (the "tag cloud" was correct, but clicking a link would bring no results, while searches of everything that wasn't a tag did bring results), so I did a fresh install. That solved the tags issue. However, the favorites handler plugin still causes the front end to throw the error, so to keep things logical, I'll start a new thread just for that issue, as everything else is working, and favorites don't work site wide (after selecting your first favorite - the issue is immediate), no matter the theme you are using.