I haven't tried flashfxp for a couple of years since i've been exclusively on linux-boxes. I got Crossover (but PlayOnLinux or regular wine-packages would works just as fine I'm sure) to install FlashFXP for me and it works as a treat.
So if you haven't tried running it through wines application layer, now might be the time
Screenshot of 4.2.5 running under ubuntu 12.04
https://www.dropbox.com/s/5uv1aya98f...ta%201_050.png