Can you post the lines you added to your wp-config.php and bb-config.php files?
The line defining the secret key in bb-config.php should look something like this:
define('BB_SECRET_KEY', 'My Secret Key');
and in wp-config.php
define('SECRET_KEY', 'My Secret Key');
Don’t forget the BB_ in fron of SECRET_KEY in the bb-config.php file.