LMcGhee As i know this is not your problem…
Actually you may be trying to do direct log in to your WordPress without registering for an account in your WordPress… That for it not work.
To use FB log in to your WordPress.
First Start your Registration as cristophergv said and Logout to your admin..
Come to main page click register… there you found SFBC link asking you to register with Facebook… When you complete your registration. you able to login with your Facebook account…
Hope it work after this…
Cheers
letmeseethis.tk
