Tried to leave a comment and couldn't? Guess what? Me, too. Blogger says I don't have a Google address. WTF? I do too, plus a blog. My research showed a ton of bloggers with this problem, and no posted solution.
This is the only thing I know that has worked - sign in with the profile "anonymous" or "name/URL". If that doesn't work, email me at email@example.com because I'd like to know so I can yell at someone. As soon as I figure out who.