A lot __() function calls in the User Registration Add-ON don't have the second domain parameter:
$form = self::add_validation_failure($config['meta']['username'], $form, __('This username is already registered') );$form = self::add_validation_failure($config['meta']['username'], $form, __('The username can only contain alphanumeric characters (A-Z, 0-9), underscores, dashes and spaces') );$form = self::add_validation_failure($config['meta']['username'], $form, __('The username can only contain alphanumeric characters (A-Z, 0-9), underscores and dashes') );$form = self::add_validation_failure($config['meta']['username'], $form, __('The username can not be empty') );$form = self::add_validation_failure($config['meta']['email'], $form, __('This email address is already registered') );$form = self::add_validation_failure($config['meta']['email'], $form, __('The email address can not be empty') );$form = self::add_validation_failure($config['meta']['password'], $form, __('Passwords may not contain the character "\"') );These strings are not available in the default WordPress (3.2+) translations.
