Error: couldn't get default input device... when running on simulator

You may need to reset your System sound preferences by toggling "Play user interface sound effects" checkbox in System Preferences > Sound > Sound Effects

sound-not-working-in-iphone-simulator

or possibly adjusting your audio input device to something the simulator likes.

simulator-crashes-on-aqmeiomanger

I am having no problem playing back .wav files in the Simulator using Actions like yours above with the sound Actions as properties of the SKScene object. So alternately there could be an issue in your SoundStore object.