WordPress MU

I use IT Damagers plugin to generate it. if I try to validate: http://validator.w3.org/feed/check.cgi?url=http%3A%2F%2Fzice.ro%2Fwpmu-feed%2F I get this error:

line 34, column 19: wfw:commentRss must be a full and valid URL: (20 occurrences)

line 34 reads: <wfw:commentRss></wfw:commentRss>

I had a look into the wpmufeed.php and found this:
<wfw:commentRss><?php comments_rss() ?></wfw:commentRss>

so it seems that if there are no comments the comments feed url is not isnerted, or is it never inserted? anyone can help with this?

I jsut noticed something a lot worse:

if someone is reading my sitewide feed with a feed reader, the links to images within the posts are broken because the subdomain.domain.com/filepath is altered to domain.com/filepath and the rewrites do not work anymore

is this standard behaviour? it looks kinda strange to me.