Did you try it with and without Passive FTP? (Site Definition | Advanced | Remote Info) Also, there are two options under the "Server Compatibility..." button that you might try. You might also try leaving Host Directory blank or "/".
I had problems too. At least the "Test" button makes it easy to try different settings. Good luck finding the right ones. You're close
did you put /public_html/ In Remote Info > Host Directory????
Dont try puting pftp on all it will do is slow it down.
Also what server is it?
and who is it hosted with?
Try asking your provider for your details.