I recently tried to activate some option in my feedburner account but it came up with error

The URL does not appear to reference a valid XML file. We encountered the following problem: Your feed has an invalid character(s) in it. This may be caused by editing your posts with a wordprocessing program. Try copying your posts into a plain text editor (like Notepad or TextEdit) before pasting them in your blogging tool.
I checked my feeds, and woha.... they are gone. I tried to google the issue but all the fixes were for 2.5.x versions. Please help me out guys :s

feed link: http://www.techreaders.com/feed/

Thank you