Try backing up and then deleting the data folder and then generate a fresh data set to see if the problem persists
Thanks jarvis24 for your reply. I tried to do what you told me, deleted the data folder, and generated a new data set.

However, the problem still persists. Some of the questionnaires are still missing and some of the variable names are also missing (showing up as v0023 or something similar).

We are running 17 questionnaires in one experiment.

Help?