I just tried to run the Flex Viewer as Administrator, but have the same problem. I will try the workaround you suggested. Creating it on my computer, then copying it over to the server. Still, I feel like there is just some small port or permission not open on the server that could fix it. And if the Flex Viewer can't get out to the ESRI basemaps....what else is being blocked that might be important in the future for ArcGIS Server functionality. Thanks for your help.