I’ve been looking for a DAAP client for the iPhone/iPodTouch for some time so was interested to try your app.
Unfortunately, I seem to get the same initial error as GaryAJ. That is, after selecting my Firefly server, I get a box saying “Connexion au serveur. Obtension des Playlists”. I’ve left it running for over half an hour and also tried stopping it and trying again, but it doesn’t seem to get any further. The screen does appear to show the Playlists listed on the Firefly webserver. I currently have about 4300 songs on the server.