I have a message from component in front and administrator

Hamid,
That message is a developer message from PHP. You can hide those types of messages by setting the "Error Reporting" to "None" in the Joomla Global Configuration area. That is the recommended way to run a production website. The settings of "Maximum" or "Strict Standards" should only be used in development sites. Again, even then, that message is not an error message, just a notice for us as developers for something we should change in our code to work with the latest versions of PHP.

no body can register in my website from JFBconnect except admins..

Can you explain what you mean by this? If you mean only people that are administrators of your Facebook application, that likely means your App is still in Sandbox mode. Go to the Facebook Developer area and disable that setting.

.and component redirect to registration form

Please ensure you've enabled the "Enable Automatic Regististration" setting in JFBConnect. That will automatically create accounts for users when they login with Facebook or Google.

I hope that helps,
Alex