I have found one problem. If you change the map maker icon then it displays as a broken png icon (except if you use the first icon which is bydefault selected).
But lets suppose you export it as a kml file, and open it inside the Google Earth, then the marker icon (png) is displayed properly.
Could you explain about this problem.
See it here: http://188.8.131.52:7070/wordpress/wp-admin/