Hi JL,
My guess is that the problem is that the account you log in with does not have access to the Automated intelligence and column actions functions. You can check this by going to Administration / Users, pick user rights for the user you log in as and check if the permissions has been granted.
The permissions are given to the Administrator account automatically for new installations of 6.3 or later, but if you have upgraded from an earlier version, they are not set.
You can absolutely try on a large table.. The AI function scans just 5000 records, so the time it takes depend more on how many columns you have.
Best regards
Bo Andersen