If the config sub folder is uploaded, open the config/validate.php file and amend the username/password. If this is set the same as the main gallery, then you only have to login once to access this.
To access the online config editor, from the gallery directory, open /config/index.php
Note: this is experimental, and has not been fully tested, be sure to backup your sp_config.php
comments.php includes some settings at the top of the script that may need amending, however I would recommned that:
$comment_settings['admin_email'] = firstname.lastname@example.org;
is amended to your own email address. If you don't you run the risk of missing a comment added to one of your images.