The feed was broken. I've attempted to fix it by implementing 5 minute caching in PHP. I'm not sure if it will fix the problem, but hopefully it will help. I don't know why the PHP script sometimes times out. Maybe there are just too many requests. This should fix that, querying the database only every 5 minutes maximum.
http://feeds.feedburner.com/GoogleRSS
If there is any problem, let me know. Thanks!