I took a look at the RSS feed that you provided to us. I ran it through a validator, and it looks like there are a number of problems with the feed making it incompatible with our Widget, and in all likelihood most RSS readers.
I would run the URL through the validator linked above, and resolve the Undefined Item Elements, as well as the encoding issue. Once those are resolved, I'd try it again. If that still doesn't work, you may need to take care of some of the smaller issues in Line 16 and 90.