yeah, same happened to me, i just unpublish the mambot CB Invite and it worked

Just got the same problem, wasnt while updating or anything. Actually I was working on a subdomain of my site and someone messages me and says is the site down. I look at it, its the same error message as stated. Find this thread, unpublish the invite plugin, everything shows up, but errors all over my site.

A little closer look and turns out I deleted my components folder. lol

Waiting on my back up to restore everything, Im sure that was MY problem. Haha.