If you know where the marker belongs (the coordinates), don't use the geocoder, just put the marker where you want it. Like this example from the Google Maps API v3 documentation
Note that the example in you post is using the Google Maps API v2, whih was deprecated May 19, 2010; and reaches end of life May 19, 2013. New development using that version is discouraged.
<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="initial-scale=1.0, user-scalable=no">
<meta charset="utf-8">
<title>Google Maps JavaScript API v3 Example: Marker Simple</title>
<script src="https://maps.googleapis.com/maps/api/js?v=3.exp&sensor=false"></script>
<script>
function initialize() {
var myLatlng = new google.maps.LatLng(-23.426056, -47.599556);
var mapOptions = {
zoom: 4,
center: myLatlng,
mapTypeId: google.maps.MapTypeId.ROADMAP
}
var map = new google.maps.Map(document.getElementById('map-canvas'), mapOptions);
var marker = new google.maps.Marker({
position: myLatlng,
map: map,
title: 'Hello World!'
});
}
</script>
</head>
<body onload="initialize()">
<div id="map-canvas" style="height:400px; width:500px;"></div>
</body>
</html>