1. Is your map service a cached (tiled) map service? Basemap layers must be cached. 2. Do you have clientaccesspolicy.xml and crossdomain.xml available on your ArcGIS Server? See the 2nd question in the FAQ help document (http://help.arcgis.com/en/webapps/sh...questions.html) for further info.
Katy Esri Product Engineer
Katy Dalton | Technical Consultant THE SCIENCE OF WHERE™