On RasPi 2 I get a ton of errors when I press ‘Play’

root@osmc:~# java -jar soundseederspeaker.jar 
SoundSeeder Speaker
Version 0.4.2 beta - built50330
Copyright 2015 JekApps - www.soundseeder.com

Network connected: 10.0.0.58
Nexus 4 connected
Play
Current Song: No song selected
Nexus 4 audio stream connected
Nexus 4 audio stream disconnected
Stop
Play
gdh-phone audio stream connected
Current Song: I:Cube - Falling
javax.sound.sampled.LineUnavailableException
Exception in thread "SpeakerPlaybackThread" java.lang.IllegalArgumentException: Master Gain not supported
	at org.classpath.icedtea.pulseaudio.PulseAudioLine.getControl(PulseAudioLine.java:89)
	at org.classpath.icedtea.pulseaudio.PulseAudioSourceDataLine.getControl(PulseAudioSourceDataLine.java:51)
	at com.soundseeder.speaker.g.a(Unknown Source)
	at com.soundseeder.speaker.i.a(Unknown Source)
	at com.soundseeder.speaker.g.a(Unknown Source)
	at com.soundseeder.speaker.g.run(Unknown Source)
Play
javax.sound.sampled.LineUnavailableException
Exception in thread "SpeakerPlaybackThread" java.lang.IllegalArgumentException: Master Gain not supported
	at org.classpath.icedtea.pulseaudio.PulseAudioLine.getControl(PulseAudioLine.java:89)
	at org.classpath.icedtea.pulseaudio.PulseAudioSourceDataLine.getControl(PulseAudioSourceDataLine.java:51)
	at com.soundseeder.speaker.g.a(Unknown Source)
	at com.soundseeder.speaker.i.a(Unknown Source)
	at com.soundseeder.speaker.g.a(Unknown Source)
	at com.soundseeder.speaker.g.run(Unknown Source)
Play
javax.sound.sampled.LineUnavailableException

If I run ‘alsamixer’ I get cannot open mixer: No such file or directory because I use a C-Media USB Audio card – it has no mixer – is there an option to simply not set the volume / mixer ?