http://forum.mikrotik.com/viewtopic.php ... or#p440806
Within Windows (and Linux, under certain circumstances), pings are special and require escalated privileges. You must run The Dude (either the application or the service, if it's running in service mode) as an Administrator. If you aren't running as a service in Windows Vista (Server 2008) and newer, this means you must actually "Run as Administrator" so that you get a UAC Escalation prompt, and choose yes. If you are running as a service, merely having the service run as a user with Administrator permissions is sufficient.