RSS trouble with mozilla (not IE)

Hi, I wanted to manage my RSS feeds with feedburner but unfortunatly it’s not working. With IE, I can display in the browser the feed but with mozilla I’ve got an error (same as described by feedburner). problem is here: http://www.creaf.be/?feed=rss2 I have disable all my plugins and have tried one by one to reactivate them and test but the problem is still there. I have checked all the code (free space) before <? ?> but also without success… I am quiet disappointed. Can anyone help me ? Thank-you.