In case anyone is wondering, I found the solution to the above problem. When you list your website in your Feed Burner widget, make sure that you write it exactly as Feed Burner assigned it. You can find this on your Feed Burner site registration page.
More specifically, make sure you include the full URL, which has FeedBurner info at the front. Beyond that, note that FeedBurner does not place a period before “com” at the end of the URL. So, for instance, for my blog, http://www.chartlottewestbrook.com, FeedBurner has it listed (after the FeedBurner part of the URL) as Charlottewestbrookcom.
Is FeedBurner case sensitive? I don’t know, but I suggest you play it safe and use upper and lower case exactly as written on your FeedBurner blog registration page.