I did receive a response regarding my issue with the JC Sports site.
Response from Blogger Team:
Thanks for letting us know about this bug with Blogger in beta. You are receiving this error due to Blogger not recognizing the URL you've entered into the Feed page element as a valid feed URL. We're looking into it and hope to have it fixed as soon as possible. In the meantime, if you remove this page element from your layout, your blog should appear correctly. We appreciate your patience and apologize for any inconvenience.
The Blogger Team
The site is accessible again, which is great, but I did not remove any feeds and do not notice any missing that I had added, so I am not sure what actually happened. I don't know if it is possible that a feed was unavailable for a time period and as a result during that time period the site would not load. I hope that is not the case, but I'll keep an eye on it.