Recently active topics in twitterfeed tagged with blog

How do I make my feed ignore comments on my blog? I have the feed set so when I post a new blog update, it sends a twitter out. Well, on that same blog, I have a section that updates whenever someone comments. How do I make is so it does not send out a twitter of that person's comment?

I get a "We couldn't parse this feed, please check the URL is valid" when I enter my Wordpress feed. Any known problem with this particular service ?

I've just entered the URL for my blog, tested 4 times and it says my URL is not valid, even though it works great on Firefox and Internet Explorer. What could be the problem?