Ciao,
ho implementato questo codice ma non riesco a far apparire il marker.. non capisco il perchè?

codice:
<script src="http://maps.google.com/maps?file=api&amp;v=2.x&amp;key=LA_MIA_CHIAVE" type="text/javascript"></script>
<script type="text/javascript">
var map = null;
var geocoder = null;

function load() {
  if (GBrowserIsCompatible()) {
	map = new GMap2(document.getElementById("map"));
	map.addControl(new GSmallMapControl());
	map.addControl(new GMapTypeControl());
	map.setCenter(new GLatLng(42.924335 , 10.755349), 17);
	geocoder = new GClientGeocoder();
  }
}

function showAddress(address) 
{
  if (geocoder) {
	geocoder.getLatLng(
	  address,
	  function(point) {
		if (!point) {
		  alert(address + " not found");
		} else {
		  map.setCenter(point, 16);
		  var marker = new GMarker(point);
		  map.addOverlay(marker);
		  marker.openInfoWindowHtml(address);
		}
	  }
	);
  }
}

</script>

<body onLoad="load();showAddress('Largo Manzoni 9, 58022 Follonica (GR), Italy');" onUnload="GUnload();">
	  <div id="map" style="width: 500px; height: 300px"></div>
</body>
Grazie in anticipo