I was getting the title error from my make-release script until I added -k <mykeyid> to the invocation of 0publish.
http://lists.gnupg.org/pipermail/gnupg-users/2006-January/027801.html put me onto that workaround, for what it's worth.
You mean that GPG couldn't sign your feed using its configured default key? Sounds more like a GPG problem... (I've added a note to the web-page, though).
Yes, it's certainly a GPG problem, but I thought it might be serious enough for ZI that you'd want to work around it somehow.