I am using this code in my flash file
import air.net.URLMonitor;
import flash.net.URLRequest;
import flash.events.StatusEvent;
var monitor:URLMonitor;
func
The air.net.URLMonitor is the AIR available class - so will not work outside of the AIR player.
But you could try to do your own as all this monitor class does is "ping" the url and check the response, so you could do similar try to load something from known source like google.com and if it completes wihtout error then it is OK otherwise you will get error.