I'm so sorry to hear that you're having issues with the audios! Sometimes the information plays faster than your computer or internet connection can access and the audio has to stop so that your computer can catch up.
If you press pause, the audios will have enough time to finish loading so you can have smooth playback. If it goes back to the beginning, you can adjust the slider to where you were when it stopped. You can also try the backup audio player links under each presentation.