Comment 7 for bug 1221304

I am experiencing this as well. After upgrade I the package appmenu-gtk and appmenu-gtk3 are no longer installed and when I try to install them, I receive this error:

Package appmenu-gtk3 has no available version, but exists in the database.
This typically means that the package was mentioned in a dependency and never uploaded, has been obsoleted or is not available with the contents of sources.list

I am attaching my unity-panel-service.log if it helps.