Feed still not working

This is a different issue than my plugin is designed to fix. I am guessing you have found the issue however because your feed does appear to be working correctly.

This looks like an issue with the NextGen Gallery Plugin, I would disable it to see if that resolves the issue. You can also try this code in your theme functions file to see if it fixes it.

add_filter( "the_content_feed", "the_rss_feedfix_2" );
function the_rss_feedfix_2($content){
$pos =  strpos($content,'<?xml version');
$content = substr($content, $pos);
return $content;
}

If the nextgen footer is in fact causing the issue you can also perhaps use the remove_anonymous_object_filter like in the article here:
http://wordpress.stackexchange.com/questions/57079/how-to-remove-a-filter-that-is-an-anonymous-object

with:

function rss_ngg_footer_disable(){
    remove_anonymous_object_filter('wp_footer','C_Photocrati_Resource_Manager','print_marker');
}
add_action('wp_footer', 'rss_ngg_footer_disable', -2);

Let me know if either of these work for you.