Thanks for the connection details that you emailed me. I've tested the connection:
1. Your server doesn't accept Passive FTP (PASV) connections. This is very unusual - it is the standard method of connection, and I would advise that you contact your server administrator to have them enable Passive support
2. When Yummy automatically reverts to Active (PORT) connections because Passive fails, it works just fine for me. I used version 1.6 of Yummy FTP.
It's possible that you're using the built-in firewall in OS X and that is causing a problem with the PORT commands. Try disabling the firewall. This is located in System Preferences -> Sharing -> Firewall. Look for the Stop button and then click it. Try your connection again.
If you still have problems, select 'Save FTP Transcript' from the File menu in Yummy FTP and send the resultant file to me at the support email address and I'll investigate further.