podcasts not downloading

When you subscribe to a podcast - as opposed to viewing it in the Store, where it can take a couple of days for new episodes to appear - the iTunes application reads the feed directly: the Store is not involved.

You could try getting the feed URL from the podcaster's website and subscribing manually from the 'Advanced' menu. If you can't get a result it usually means that the feed server is not responding or the feed is invalid in some way; unless your firewall or something in your connection is blocking the connection to these servers.

You might like to post the Store URL of one of the podcasts you're having trouble with it so others can check it: control-click on the podcast image and choose 'Copy link' to get the Store URL.