And also you don't have to use the "delay" approach:

var onRender = function(){
    var dataregion = qwp1.getDataRegion();
    dataregion.hideMessage();
};

var qwp1 = new LABKEY.QueryWebPart({
    schemaName: schemaName,
    queryName: queryName
});

// note the absence of the "renderTo" config option

qwp1.on( 'render', onRender ); // I believe, "onRender" method must physically in the code precede this call
qwp1.render( 'MyDiv' );