Oh, you're using AROS as the server? You might have better luck using an AROS FTP client. I think there are built-in options to enable an FTP server in OS X (depending on the version).
I've built an AROS machine with Intel Pro NIC. Anyone experience connectivity issues during batch uploading ADFs via FTP?
Have you set an ACTIVE or a passive FTP connection to the AROS server? In case you're using Icaros' internal ftp sharing feature, you need to set an ACTIVE connection from the client side, or no transfer will be possible.