use this code for the tabs onclick instead:
<li class="TabbedPanelsTab" tabindex="0" onClick="window.setTimeout('google.maps.event.trigger(map2,\'resize\');wagmp_map_2_obj.obj.setCenter(wagmp_map_2_obj.points[0])',30);">Dorchester Christmas Trees</li>
<li class="TabbedPanelsTab" tabindex="0" onClick="window.setTimeout('google.maps.event.trigger(map3,\'resize\');wagmp_map_3_obj.obj.setCenter(wagmp_map_3_obj.points[0])',30);">Weymouth Christmas Trees</li>