I was able to get the link before it was removed.
The file imported without any errors.
Of course, I don't have the media, but I can open the long compound clip and see the many titles inside.
Try deleting preferences (always a good idea when something is not working well in the application).
To delete preferences, hold down command and option while starting FCP X and click Delete Preferences.
The application will start in a default state, and open an "Untitled" library.
Reopen the library you were working on, set the preferences the way you like them, and try again.
Another thing: does FCP have Full Disk Access in System Preferences->Security & Privacy->Privacy? It should.