Thanks for advice Moderators although not entirely successful in my case.
I now have a V8 and a V9.03.
The V8 can't load the "pjc" because it was created by a later version of TMG. Neither can it load a "sqz" backup because that triggers the "FoxPro" problem.
The V9.03 loads and runs the current "pjc" and as far as I can tell all the data is fully accessible. However I cannot backup/restore or backup on exit as each again triggers the "FoxPro" error.
The V9.04 installs but will not run triggering the "FoxPro" error immediately on attempting to run.
I have run the 32-bit cmd.exe solution with apparent success at various times before and after loading, uninstalling or reinstalling TMG V9.03 or V9.04 but with no impact on the "FoxPro" problem.
The fact that I made the crucial error of running the 64-bit cure originally may, I suppose, have left something undesirable in the registry although the response to the command was that the file was "not found".
Any further help would be most welcome as I can add/subtract data at V9.03 level but I can't backup or restore, which is a fairly crucial requirement.