We're not starting the programme from the shortcut. When you insert the DVD it comes up with a window with a number of option buttons, one of them is to 'play', so you click that and it starts (on my user, but not his).
It was originally installed on his profile, but wouldn't start, so we uninstalled it and installed it again on mine, it started OK. So we then uninstalled it again, and reinstalled it on his profile but it wouldn't start. Now we've reverted back to previous (installed on mine)and it will only start from mine.