Subscribe to Comments 2.1.2: How to modify checkbox language?

I just activated the plugin Subscribe to Comments v. 2.1.2, and I’m trying to modify the checkbox language: “Notify me of followup comments via e-mail”. Does anyone know how to do this?

I already tried modifying the following code in the subscribe-to-comments.php file:

function db_upgrade_check () {
		global $wpdb;

		// add the options
		add_option('sg_subscribe_settings', array('use_custom_style' => '', 'email' => get_bloginfo('admin_email'), 'name' => get_bloginfo('name'), 'header' => '[theme_path]/header.php', 'sidebar' => '', 'footer' => '[theme_path]/footer.php', 'before_manager' => '<div id="content" class="widecolumn subscription-manager">', 'after_manager' => '</div>', 'not_subscribed_text' => __(<strong>'Notify me of followup comments via e-mail</strong>', 'subscribe-to-comments'), 'subscribed_text' => __('You are subscribed to this entry.  <a href="[manager_link]">Manage your subscriptions</a>.', 'subscribe-to-comments'), 'author_text' => __('You are the author of this entry.  <a href="[manager_link]">Manage subscriptions</a>.', 'subscribe-to-comments'), 'version' => $this->version));

However, when I modified the line for “Notify me of followup comments via e-mail,” the language did not change when I logged back into wordpress. I also tried uninstalling the subscribe-to-comments.php and comments.php file in my themes, and then reinstalling both (I thought that the page might have been cached somehow on my server), but that still didn’t work. Is the language controlled by a different file? Is the function db_upbrade_check controlled by one of the wp-includes file?

Thankfully, I was able to change the “Subscribe without commenting” language by modifying the following code in the subscribe-to-comments.php file: <?php _e(‘Subscribe without commenting’, ‘subscribe-to-comments’); ?>

Thanks in advance for any help.