Read only on ftp connection?

I doubt it is the filesystem as the FTP server should be handling file IO.

Try in the Terminal. There are several ways you can connect.

It is basically ftp user@host, but you can type man ftp to see a list of ways to add username and password, port, etc. Once in man, type q to quit.

Once you log in, you'll have an ftp> prompt. Use the ftp commands to "put" or "get" a file, and "ls" to see what is there. The rest of the commands are in the man page.

Basic FTP has pretty much been dropped from OS X as it is completely insecure. However, I'm not sure why a third-party ftp client had trouble. Maybe it was how you logged into the server.

If he's controlling the connection, maybe he only gave you read permissions.

If he's controlling the connection, maybe he only gave you read permissions.

I believe the command line will respond with error codes which might indicate if it is misconfigured.

I think your friend has shut down the ftp server. He likely did not configure it correctly to accept your upload connection, hense your initial problem.