Facebook will only return an email address for the user if it's been validated and active for the account. The only times we see it not being returned properly is when old accounts are being used to test. Since the account isn't very active, Facebook doesn't return the email address. In that case, JFBConnect does what it has to and asks the user for their email address.
I just tried to register on your site, and got the following error message:
28
ERROR: 28
connect() timed out!
I'm not sure what the cause of that is. It sounds like your server is timing out while trying to communicate with Facebook. You also didn't attach anything to the previous post for the IPv6 error. The issues may be related once we see the image.
Thanks,
Alex