While launching Picture Arena, the sound output (e.g. via iTunes®) is shortly interrupted.
When Picture Arena is launched, it also initializes the speech recognition functions. This seems to lead to a short interruption in the sound output. If you do not need the speech recognition features in Picture Arena, you can turn off this feature in the Picture Arena preferences. Right now, we are not aware of any solution to this problem - it appears to be a general problem with the speech recognition in OS X itself.