Peter, The N-Kato-Unitram file is shipped inside the product itself. Go to File->Parameter Files->Library and search for Kato. The Unitram file should be listed. Hit "Add" and then "OK".
The old parm file would still be loaded at startup in Mac case even after being deleted from Windows because they have different settings files so it needs to be removed from each using the Parameter Files Menu. (Unload).