Improper use of format_plural()

Hi, I just found weird usage of the format_plural() and drupal_set_message() in this module code.

drupal_set_message(
      format_plural(
        count($not_received),
        t(
          'There was a problem processing your application for: %roles',
          array('%roles' => implode(', ', $not_received)), 'error'
        ),
        t(
          'There was a problem processing your applications for: %roles',
          array('%roles' => implode(', ', $not_received)), 'error'
        )
      )
    );

There is no 'error' parameter for t(), format_plural() already using t() for it's strings…