Anyone know what I'm doing wrong with my RSS Feed?

[LeonP]

Hey all. I'm running Before Dawn Bar ( http://lianx-design.deviantart.com/art/Before-Dawn-RM-Bar-188602159 ) and have a few skins meant to serve as Readers for different RSS feeds. I've got a few working, however this one just doesn't work no matter what I do.
http://blogs.valvesoftware.com/category/economics/

Using the RSS Feed link as a source isn't working, and I'm not sure what I'm doing wrong. It's the only one I'm trying to use not located on feeds.feedsburner.com, so could that be it? Any help would be appreciated!