- Is the PC on the same network as your Mac -- meaning does it take the same network path to get to the FTP servers?
- Are you behind a firewall? If so, you may need to ensure you are forcing passive FTP from your client.
- Are these public/anonymous FTP servers? I'm guessing they are from your attempt to use "Guest" as the account. The standard account to use for public FTp servers is "anonymous" and for your password, your email address (or at least something formatted like an email address). See
http://en.wikipedia.org/wiki/File_Transfer_Protocol#Anonymous_FTP
As for clients, I've had the best luck just using FireFox for FTP things on my Mac. I'm behind a firewall and a squid proxy and Firefox is the only thing that seems to work reliably (though OpenBSD images and patches seem to be the only thing I use FTP for these days).
Hope that helps.
