Spotify - Still a Problem

I installed Volumio 1.51 on a RPi B+

I then installed the packages build-essential and wiringPi library using apt-get install

Spotify does not start.

Output of pstree:


Log File /var/log/spopd.log:

[ERR ] Can’t load sox audio plugin: cannot open shared object file: No such file or directory

I disabled Spotify, rebooted, enabled Spotify, rebooted, but the problem remains.

I am using a Spotify Premium account

Any recommendations?