If you are running in a client SKU (Windows Vista or Windows 7) you need to install support for Remote Management:
x86:
http://go.microsoft.com/?linkid=9655671
x64:
http://go.microsoft.com/?linkid=9655672
Also make sure the server enables Remote Administration (WMSVC) by: Inetmgr.exe -> Server -> Management Service... enable remote connections and start the service. also make sure to make it auto-start inside the Services snap-in so that if you reboot the service, WMSVC comes back.
More info: http://learn.iis.net/page.aspx/158/remote-administration-for-iis-manager/