Hi. I agree with what others have said about this issue. Assuming that you never meant for your participants to provide vocal responses, the easiest thing to do is to simply review each .que file on each computer, check the Item Type column for instances of "Voice Response".

Making sure that option is not specified will indicate that there could be a problem with MediaLab.

If you know that no Voice Response option is specified in any of the files you are using on each of the machines that you are using, then I recommend that you share one of files with the group, so we can review for clues.