Blocks have disappeared

Last week I installed the multiblock module and created an instance of the domain_nav block. It worked great, but yesterday both the new instance and the original blocks have disappeared. I'm not sure how they would have both gone away. I've checked the disabled blocks, I've disabled, uninstalled and reinstalled the modules with no luck and now I'm out of ideas.

Anyone have ideas what happened and what I can do to get this to work again?