I downgraded to the previous version of music app. (in settings, applications, I choosed “uninstall updates”) and now I can download again songs. :-)
My post was not complete : I can search for songs with the previous version but I can not suscribe to VIP status. So I tried to upgrade again music application / suscribe to VIP status. It worked for the status, but same problem : impossible to search for songs. So I hoped that downgrading would permit me to search for song with keeping my VIP status. It doesn’t work : on previous version I can search for songs but I lost my vip status. On last version I have the VIP status but can’t search for songs.
I solved my problem
With the new version of music app, you need to be connected from china to be able to search songs
So I used A chinese proxy (http://www.freeproxylists.net/fr/cn.html), for example 188.8.131.52 port 80.
To set it you touch your wifi connection during 2 seconds…