NullPointerException in sound

Ever when I try to run any example of sounds throw the follow error:

java.lang.NullPointerException

at Jogo..setupSound(.java:181)

at Jogo..simpleInitGame(.java:132)

at com.jme.app.BaseSimpleGame.initGame(BaseSimpleGame.java:545)

at com.jme.app.BaseGame.start(BaseGame.java:74)

at Jogo..(.java:88)

at Jogo..main(.java:81)



Lines of error:

comfirmaSound.setType(AudioTrack.TrackType.POSITIONAL);

comfirmaSound.setRelative(true);

comfirmaSound.setLooping(true);

comfirmaSound.setReferenceDistance(1f);

comfirmaSound.setVolumeChangeRate(1f);

comfirmaSound.setCurrVelocity(new Vector3f(0.1f, 0.1f, 0.1f));

comfirmaSound.setWorldPosition(0, 0, 0);

comfirmaSound.setMaxAudibleDistance(1f);

comfirmaSound.setMaxVolume(1f);

comfirmaSound.setMinVolume(0.1f);