Exact same thing is happening to me. DNR-202L and one of my DCS-934L cameras go offline when viewing in mydlink.com webpage. Rebooting the 202L and unplugging then replugging the camera brings everything back. As with the other users when mydlink.com can't see the two devices my LAN can see and access them normally. This has been happening now for about 1-2 weeks.
Thought at first that when it started that my equipment was going flaky - now I'm not so sure. Given that it is happening to others, all within the same time frame, leads me to think that something is not quite right on the mydlink end . . .