If you find yourself needing to upload files to our FTP site from behind a firewall you'll need to use a client that supports "passive" mode. Anyone knowing of such a program is asked to let the rest of us know.
CuteFTP. I think a number of support people already have it.
My recommendation for customers who find themselves behind Stalinist firewalls would be to complain to their network administrator though. This is a bug at their end.