I have replaced the files in the Twenty Ten theme with my own index.php and associated files and did some PHP hacking and the feed is working! I wish I knew about this before, but the thread here: http://wordpress.org/support/topic/custom-indexphp-invalidates-rss-feeds gave me this idea.

This is a command that will list the contents of your crontab file if you have one. You need to use the sudo command as unprivileged users are not allowed to list the contents of this folder. The best way to view the contents of your crontab file is to use the crontab -l command. …