Thank you for the note! Another fellow in Italy is having trouble, too, and I wasn't sure where to begin. Now I've got some ideas.
I believe you are correct: Apple has again tightened up its security, preventing applications from having access to various places in the file system to programs that have not been granted that permission explicitly. {sigh} I have a laptop with Catalina that I can use for testing. If it is a permissions problem, hopefully I can find a solution quickly.
-- Scott (NE1RD and Author of CabConverter)
NE1RD B. Scott Andersen