Thanks for your quick response, Derek. I am using 3 map services: the Esri World_Terrain_Base, my own PA_Landforms regions and subregions (2 feature classes in one map service), and my own PAplaces for cities/towns (as points, layerID=0) and cities (as polygons, layerID=1). I think I have the map service URL for the PAplaces map service specified correctly.
I apologize for not using the HTML code tags, but I'm not sure how to do that.