Problem solved. I got the plugin from this site http://tech.reumer.net/google-maps/
I emailed the developer (Mike Reumer) and he suggested the following code change, which I include below if anyone else runs into the same problem . A big thanks to Mike and to you also Hain84 for your interest
Can you try to edit index.php in the root of Joomla and add at line 84 after $mainframe->triggerEvent(‘onAfterRender’);::
JPluginHelper::importPlugin(‘content’);
$tmp_row->text = JResponse::getBody();
$tmp_params = new JParameter(null);
$mainframe->triggerEvent(‘onMap’, array( &$tmp_row, &$tmp_params ), true );
JResponse::setBody($tmp_row->text);