RSS Feed isn’t working anymore

My RSS feed was working but then I moved host and I’m having problems.

http://www.videogame-news.com/feed/

I’m guessing if this bit is sorted

Warning: Cannot modify header information – headers already sent by (output started at /usr/home/game/public_html/index.php:5) in /usr/home/game/public_html/wp-rss2.php on line 8

Then it will work but I’m not sure what to do about that?

Thanks in advance.