Have you rebooted or done source .profile
Typing the port command while in /opt/local/bin wouldn't help because it would still be interpreted as a command to be done according to path. Youwould have to do
sudo ./port selfupdate or whatever command you wanted.You also might need to edit your /etc/profile instead since you are using sudo but if you do that you must reboot or use "source" to update it.
