Try backing up and then deleting the data folder so MediaLab can create a fresh data folder and fresh data files with the updated structure. It will do so if you run a trial session after deleting the old data folder. Then, take a look at the new data files (i.e., after the trial run) and see if the new files are more like what you would expect. If not, let me know and I'd be happy to look over the files for you.