I have just figured out a way to bypass the CalDAVEntityQueableOperation error or something along those lines, however it is painful. Turn off iCloud calendar synchronization on your mac, and create a new calendar on your mac called Test. Double click the .ics file, and then add it to the Test calendar. Now turn calendar synchronization back on. Click merge when prompted, and open the calendar app. Wait while it finishes, rename your calendar, and you are successfully moved.