This afternoon we released a bug fix for the Angelfire Site Builder that we hope will clear up any lingering issues with the error: "Module no longer exists"
The bug fix does two things specifically:
1. It puts the Add-on Module frame back around anything that was broken before so that at least you can A.) see what it was and B.) delete it and re-add it if you like. That will almost always fix the issue.
2. It also allows the content to appear on the published site. That ought to prevent things like images not appearing on the published site but instead just showing a blank area where the image (or guestbook or counter etc) ought to be.
As usual I look here for your comments if you have any and try to answer questions about this and/or report any additional issues to the Developers.