Ho scritto così...ma non va! Se commento il map.setCenter non si vede niente!

Da notare che ho aggiunto la variabile address! E' giusto far così?
codice:
var address = 'corso umberto, 50, 95024, acireale, it';
var geocoder = new GClientGeocoder();

function showAddress(address) {
  geocoder.getLatLng(
    address,
    function(point) {
      if (!point) {
        alert(address + " not found");
      } else {
        map.setCenter(point, 13);
        var marker = new GMarker(point);
        map.addOverlay(marker);

        // As this is user-generated content, we display it as
        // text rather than HTML to reduce XSS vulnerabilities.
        marker.openInfoWindow(document.createTextNode(address));
      }
    }
  );
}