I've got a mixed network of Macs and Windows, wired and wireless. The Macs can all see my M1001, by the Windows box cannot.
The Roku can see the Windows box when it is running iTunes, but the Windows box doesn't show the Roku in the Network Places window.
Running the UPnP Tester, referred to elsewhere, that sees the M1001.
Still no icon in network places, and the web interface only works if I specify the IP address.