Strange RSS feed problem

Hello,

My RSS feed is suddenly blank. What is strange however is that the feed is now visible at a different link. The original is blank:

http://www.rosstraining.com/blog/feed/rss

I can now see my feed here:

http://www.rosstraining.com/blog/wp-rss.php

I did not change the permalink structure, so I’m not sure what could have caused this sudden change.

The same is true for my comments feed. It too is blank:

http://www.rosstraining.com/blog/comments/feed/

I found the following link, which shows a few possible changes that I could make to the .htaccess file to redirect readers to the current working link, but I’d rather simply restore the original settings.

http://codex.wordpress.org/WordPress_Feeds

Has anyone encountered a similar problem and/or know of a resolution?

Thanks