Unfortunately can't get it to work. It just sits there saying "Starting" and nothing happens. No reaction to any button I push. As it works for many users, the problem may be on my end, but since I cannot figure out, what the problem is, I will have to deinstall it again and stick with HTTrack.

Update: After the reply from Victor I checked it out again. Evidently after installing it as a Firefox Add-on it still needs to be installed locally (reading the instructions carefully I kind of understand that now, but it was not clear to me from the beginning). But after registering the RDF it now just sits there saying "Loading...". So it still is not working for me. But I will give an extra star for the really fast reply from the developer.