Invisible directories and files using FTP

I have setup an FTP access on my desktop at home using Ability Server 2.27. When I access my FTP server from my laptop using Directory Opus it connects to it without a problem but does not list any directories or files at all. Looks like nothing on there. I tryed using different software: CuteFTP, ExplorerPlus, WS FTP, even IE - they all work fine with my FTP server. What's the deal with Opus? It's an outstanding file manager and I want to use it to manage my FTP also!

See FAQ: I can't get FTP to work.

It's probably the first thing it mentions which is the PASV mode setting.