when i view source of the page, the a href attribute is blank.
in the index.php page for the lightbox and full size gallery type, there are 3 url variables that get passed:
$gallery = get_gallery(get_mediarss_url('gallery=' . $pg_id . '&thumb=62c&full=782p&super=1024p'));
it looks like you removed the last one when when editing it to include your custom size