When people register/login using the Janrain widget (formerly called RPX) they use their password from whatever provider ie google twitter, facebook, etc, but we don't get access to that password (and we shouldn't) so we generate a random password that we attach to the user (because we don't want our internal password field to be blank) and that is what is returned by our password recovery and the user could use that to sign in using our normal login instead of their external account via Janrain. But that password won't work with the Janrain login.
I don't know how a user could end up with a blank password. Nor do I know how they would have your email for their openid.
Allow open id is not required for using Janrain (though Janrain uses open id), it is a different thing that is much less user friendly.
Some of the providers supported by Janrain have to be activated separately by you logging into the janrain site and configuring them. Facebook and Twitter I believe require you to get an api key from them that you have ot enter in your Janrain configuration.
Hope that helps,
Joe