Hi,
Try uninstalling 11.1.0.126 and then re-install the newly released version of iTunes for Windows, 11.1.1.11.
The Refresh button now seems to work, and new podcast may get downloaded.
Why aren't Cnet podcasts downloading? I used to listen to about 7 Cnet podcasts. Only 1 of them still downloads.
What happened?

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic