LW is telling you that it cannot download the file until it finds a source for it. On this network, files are shared among peers (i.e., no servers). Therefore you can dl only those files that are shared by the users to whom you are currently connected. If none of them have the file you want, you'll get the "Need more sources" message.When one of your peers goes offline, LW will automatically connect to another (who may or may not have the files you want). You can expedite this by going to Connections and removing a few peers. LW will then find other peers and search them for your files. You'll also get a new set of peers each time LW re-starts.