Hey Geoff,
Actually it is a bug -> there should not be any error, but a message telling you what is going on and I need to fix this. (and I'll output a better error message for the next version, thanks!)
You need to have a link to the map view -> it can be hidden, but you need one ( actually I was planning to remove the "back to map" link).
About the "error loading feed data" is related to this one:
forum.joomla.org/viewtopic.php?t=279064
We use the standard functions to load the feed. On some servers the certificate chain is missing or is not up to date and that is why the server actually refuses to load the data.
Regards,
Daniel