This is the problem when having to deal with external programs... (and why I prefer to do program myself when it's possible!)

Deezer (the site which offered the music player) has changed, and the embedded music player with it. Not mentionning that the new one is really not nice compared to the previous one (you can't choose which music to play...), it caused some errors on the site. So, I have decided to disable it until they solve that problem (hopefully)

They've said they will offer to use the previous music player soon, so I hope this is true...Stay tuned.