Hey Kate,
Sorry for the delay in my response, but I had some difficulties finding the right code
Open the file components/com_hotspots/views/showaddhotspot/tmpl/default.php
and go to line 44:
alert("Status Code:" + response.Status.code);
and change it to this:
//alert("Status Code:" + response.Status.code);
You can also use template overrides to change this file. Well this should disable the error, but I'm not sure if it is good or not, because when you move a marker to a position that cannot be located the user won't be aware of this and will save the marker anyway, and will be impossible to show the marker.