In an event that you update your mac, your mac firewall might be turned on “literally”. To fix this, Open terminal and open the port for FTP access. (becareful not to open all). The following is tested on MacOSX 10.6 Snow Leopard.
$ sudo ipfw add allow tcp from any 20,21 to any 1024-65535 in
YOU WILL BE ASKED FOR AN ADMIN PASSWORD!