The Flickr importer has trouble with my website's list of authors, for some reason in the importer interface (/wp-admin/admin.php?import=flickr) the form ends at:
Author of imported posts
where the dropdown is empty and the rest of the form isn't even rendered in php - there are no other fields or even a send button.
It looks like there's a bug there somewhere. Let me know if you want to look at the wp-admin of my site.