I just downloaded version 2.1.9 of WP-OpenID and haven't gotten it to work at all. I was also running Admin SSL - I turned it off, but it didn't work either way.
I have an ID at Verisign and at Google. Neither worked. Failure was slightly more obscure with SSL turned on.
With SSL turned off, I'd be redirected to the login page which would report that the OpenID log in failed.