If the td4-converter in the program does not make a Foundlists table, I'm afraid that there is nothing that you can do to fix this (without manually messing with the database structure).
Are the image files still on this computer? If so, it would probably be better to re-scan those into a new database.
Or, maybe you could re-install your older version of ThumbsPlus and use that? Most older software works OK on newer Windows versions as long as you install it in a dedicated folder (for instance, C:\THUMBS7), and NOT in C:\Program Files. However, if you should do this, I would be careful never to use system folders like My Documents, Fonts, Desktop (etc.) in ThumbsPlus.