I can configure Last.FM, and it works, but if I add a new user, and log in as that user, it gives me the message about Last.FM not being configured. I can link it for that user, then the message goes away from that point on. Not horrible, but slightly annoying. Not sure if anyone else is seeing the same thing.
Just wanted to say great job on this! Especially the artist radio, top tracks, and similar artists. These are must have features for me, and you did a great job implementing them!