It appears to be occurring in Chrome Version 24.0.1312.56 on OSX–I’m not having any problems in Firefox 16.0.1 or Safari Version 6.0.2 (8536.26.17). Also, the map itself is not loading in Chrome (the rest of the plug-in gui loads).
The error in the Chrome Console says:
Uncaught TypeError: Cannot read property ‘LatLng’ of undefined admin.js:28
methods.buildMetaBox admin.js:28
(anonymous function) admin.js:121
v.extend.each load-scripts.php:3
v.fn.v.each load-scripts.php:3
$.fn.pronamicGoogleMapsMetaBox admin.js:120
(anonymous function) admin.js:126
l load-scripts.php:3
c.fireWith load-scripts.php:3
v.extend.ready load-scripts.php:3
A load-scripts.php:3
