basecamp 4.8.12 on Mac won't upload kmz, kml file or converted gpx file

Exporting a kml/kmz from custom google map with lots of pinpointed locations for dumping, donating, recycling etc and cannot import the file into basecamp.    Have tried all 3 formats.  gpx says it is not formatted correctly, kml and kmz don't upload or give an error but nothing is imported.