I attempted to use your pliugn on my test site today, and when I attempted to login with one of my OpenID logins, I proceeded to the verification page, and then when I confirmed the login and being redirected back to my site, I received a large number of errors regarding the header being sent already.If you would be able to provide some information regarding this problem please let me know, should you be able to help me, I will provide a well written review of your pliugn and as such hopefully encourage more people to use your pliugn.
