When anyone uploads a file to BCN, the FTP server software removes the "group write" access on the file. If multiple authors are collaberating on a site, this prevents others from editting the file in the future.

This behavior can be overridden for a directory (including it's subdirectories) by creating a file called ".ftpaccess" with the following line: 

     Umask 002
ProFTPD's config is in /usr/local/proftpd/etc/proftpd.conf

More information on ProFTPD is available on http://proftpd.org