Rawhide’s a bit wonky today. XULRunner has finally landed – hooray! – but unfortunately it wants to obsolete firefox < 2.1 and replace gecko-libs. This causes trouble with stuff that uses gecko-libs (like yelp and liferea), and – of course – firefox, since we're only at 2.0 in the repos.
So, skip the 'xulrunner' update until we get this worked out.