problem in markerclusterer.js

i have an problem and error when include markerclusterer.js in开发者_开发问答 my code.. when i run the program, the error below shown:

Microsoft JScript runtime error: 'GOverlay' is undefined the error code is ClusterMarker_.prototype = new GOverlay();

it is happen on markerclusterer.js... please help me if u know the solution...

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Are you including the markerclusterer.js file after the main google maps include with your key? The map gmaps2 lib needs to be loaded first.