RSS2 Feed will not validate.

http://feedvalidator.org/check.cgi?url=http%3A%2F%2Fwww.timeout.com%2Fchicago%2Foutandabout%2Fwp-rss2.php

There are the reslts. Reading the help information, I’m assuming the issue is with the white space before the XML declaration. My question is, where is that coming from?

Someone did make a change to the wp-rss2.php file last Friday. It was causing a different issue, so I removed the change. After I did, this error appeared. I’ve even tried copying a brand new version of the file from my test server. Still receiving the error.

Any ideas?

edit: Spelling.