Alright - so I restored, then re-upgraded. This is a major upgrade so it kills all customization of the theme and other addons. Things might look a little ugly for now, but I'll fix them when I wake up tomorrow. Please report back here if you see any errors!
UPDATE - We're still having some trouble sending emails through our relay. You may not receive updates to your threads until this is fixed. We apologize for any inconvenience and we're working through the issue now.
Full disclosure - this was a major upgrade, but we had been putting it off for a long time because the addons we used weren't yet compatible. We finally decided to move forward with the upgrade though because we were starting to notice some buggy behavior and other things weren't going to be supported much longer on the previous version (facebook integration, etc.). Overall, this version seems to be a major improvement, but it's just a matter of replacing the functionality of the apps we had and re-configuring templates, etc.
The one thing we didn't think we'd have a problem with is sending emails, so that's pretty frustrating. Also, we didn't intend to run into the issues that causes us to lose a few threads and avatars - so we're really sorry for that.
Avatars should be fixed and email is working again.
The only problem remaining is that we lost some threads from Friday, May 3. We're not going to be able to recover those. We sincerely apologize. Next time we'll run through the upgrade twice on our test server before we even begin! =)