function addDoctorLocation(options) 
{
    var gm = Ext.getCmp('mygooglemap');
    var mpoint = new google.maps.LatLng(options.lat,options.lng);
    var marker = gm.addMarker(mpoint,options.marker,false,false, options.listeners);
    infoBubble = new InfoBubble({
            map: gm,
            content: '<div class="phoneytext">Some label</div>',
            //position: new google.maps.LatLng(options.lat, options.lng),
            shadowStyle: 1,
            padding: '10px',
            //backgroundColor: 'rgb(57,57,57)',
            borderRadius: 5,
            minWidth: 200,
            arrowSize: 10,
            borderWidth: 1,
            borderColor: '#2c2c2c',
            disableAutoPan: true,
            hideCloseButton: false,
            arrowPosition: 7,
            backgroundClassName: 'phoney',
            pixelOffset: new google.maps.Size(130, 120),
            arrowStyle: 2
        });
        infoBubble.open(map, marker);
}
Success added the marker on map, unfortunately infoBubble nothing has shown? why?
and dont have any error on FireBug
UPDATE HOW TO CALL THE FUNCTION
tree.on('checkchange', function(node){
        var data = node.data;      
        if (data.checked == true){
        var lati,longi; 
        var record = MarkerStore.findRecord('MainID', data.MainID)
        if (record){
        lati = record.get('Latitude'); 
        longi = record.get('Longitude'); 
        }else{
        Ext.MessageBox.show({
        title: 'Error !',
        msg: 'No Record Found In Database ! <br />',
        icon: Ext.MessageBox.INFO
        }); 
        }       
        var options = {
        lat:lati,
        lng:longi,
        marker: {title:"Hello World!"},
        listeners: {
                     click: function(e){
                                         }
                    },
                    MainID: data.MainID     
        }     
        addDoctorLocation(options);  
        } else {
        markers[data.MainID].setMap(null);
    }   
    })
UPPDATE For @Ankit
var markers = {};
var openedInfoWindow = null;    
function addDoctorLocation(options) 
{
    var gm = Ext.getCmp('mygooglemap');
    var mpoint = new google.maps.LatLng(options.lat,options.lng);
    var marker = gm.addMarker(mpoint,options.marker,false,false, options.listeners);
    markers[options.MainID] = marker;
     var infowindow = new google.maps.InfoWindow({
        content: 'Hello !',
        maxWidth: 200
    });
    google.maps.event.addListener(marker, 'click', function() {
        // added next 4 lines
      google.maps.event.addListener(infowindow, 'closeclick', function() {
          openedInfoWindow = null;
      });
      if (openedInfoWindow != null) openedInfoWindow.close();  // <-- changed this
      openedInfoWindow = infowindow;
      infowindow.open(gm, marker); 
    });
still can't close the infowindow,when clicked marker get this error
TypeError: b.O is not a function
[Break On This Error]   
(82 out of range 43)