One odd thing - when the venue website is left blank - and is reflected as such in the feed - instead of just leaving the venue name, it makes the venue a link to the current page.
The PHP seems to suggest that there should be no link if there's no URL, but Firebugging a show with no URL gets:
<a class="slushman_adp_venue_link" href="">
Not browser-specific. Firefox and IE both.
Hope this is helpful!