Hi Robert,
I've got a dynamic map service with ID of "editsLayer" that I created and instantiated in actionscript as a module level variable. I added an event listener to it: editsLayer.addEventListener(LayerEvent.LOAD_ERROR, onMapServiceLoadError);
Then, in order to test the "onMapServiceLoadError" function, I stop the map service, run the app with a breakpoint in the below function. I inspect the "event" object and nowhere in there is reference to the layer ID "editsLayer". I only see the generic id "ArcGISDynamicMapServiceLayer22" as you noted. In order to meaningfully have an Alert message such as the one below, I'd like to be able to see the actual ID of the layer that errored out and not the generic ID.
private function onMapServiceLoadError(event:LayerEvent) : void
{
Alert.show("Failure loading Map Service: " + event.layer.id ....);
}