This Forum Beta is ONLY for registered owners of D-Link products in the USA for which we have created boards at this time.
Not sure if this helps, but look at the Application Management menu and make sure NFS Services ,AFP Services and/or Multimedia Services, are enabled, if you are trying to use these services.
I had the exact same problem. After countless tries (including several firmware re-installs), finally solved it by uninstalling elfinder... hope it helps someone.