First, I would recommend starting with a sample that uses the latest version of the API: http://help.arcgis.com/en/webapi/javascript/arcgis/help/jssamples/map_dynamic.html
Next, it looks like you need a class="tundra" attribute on your body tag. Also make sure you're using the proper layer type for you map service. Is your local service tiled/cached? If it's not, you need to use ArcGISDynamicMapServiceLayer(), not ArcGISTiledMapServiceLayer().