>How should I interpret the message "blocking call cancelled" in an FTP program (WS_FTP LE, which is freeware)? It seems obvious that when this message appears, I am having a lousy Internet connection, but what is the message supposed to say?

Sounds like you have SP2 installed with the Firewall turned on...

I have an application that uses port 21 (FTP), SP2 Firewall detected access and tried blocking it, I specifically told firewall to unblock it, yet, the port was still blocked.

If this is whats happening, you can either turn the firewall off or open port 21 on it.

If not, then contact the programer, as he is the one who can tell you what triggered that error.