import mx.controls.Alert;
import mx.styles.StyleManager;
import mx.events.StyleEvent;
private function changeCSS( name:String ):void{
var styleEvent:IEventDispatcher = StyleManager.loadStyleDeclarations( name, true );
styleEvent.addEventListener( StyleEvent.ERROR, showError );
}
public function showError( event:StyleEvent ):void
{
Alert.show( event.type );
}