Thanks. I have ran the experiment, with some changes. You will need to keep the ‘participant’ field in the experiment info fields in Experiment Settings. This field is used to create your filename and will throw a name error if it is not defined.
As for the looping of sounds. I used a simple .wav file and looped for a duration of 10 seconds, and had no problems. Is it possible one of your sound files are causing the problem? As you are playing sounds sequentially, and the error is always raised after the second trial, then perhaps there is a problem with the 3rd (or second) wav file in the list. If you could inspect the sound files and let me know, that would be helpful.