Well, there are two different links. In the header there is http://healthynaturallyclub.com/?feed=rss2, while in the sidebar there is http://feeds.feedburner.com/HealthyNaturallyClub.
Why is that? Obviously because the underlying code is different. Just replace the rss2 link with the one from FeedBurner (if this feed is actually the one you want to provide) and you should be fine.
// Edit
Check your sidebar.php (or whatever file your sidebar is contained in) for the code that is being used there for the feed.
You found the right lines in your header.php but it seems, the function is either not the one that is being called in the sidebar, or the option pp_feedburner_id is different from when it is fetched in the sidebar.
If you want to hardcode the link, you have to remove the lines 313-318 and 321-323 (or put a hash # before 314, 316, 317 and 322) and replace <?php echo $pp_feedburner_id; ?> with http://feeds.feedburner.com/HealthyNaturallyClub.