Are you using posts in a CMS-type way? I am, and my site has the same problem, because I have nothing in the “Anchor text for blog” area. I think it’s still inserting a placeholder for that blog anchor text, and adding the extra separator as if something were there. Which it isn’t!
Yes, I’ve made posts solely for the purpose of generating rss. My blog site is http://creatingwebsuccess.com/websuccessblog/ and NONE of the rss/atom URLs are generating anything. I’ve read this site’s documentation and can’t find a clue… all the suggested URLs yield zippo. Like I said, I hope it’s something obvious & simple… that someone can tell me to change!