I have a Windows 7 Ultimate x64 machine that is on a domain that will not play DRM protected content from Netflix. It gives a N8152 DRM error. I have uninstalled and reinstalled Silverlight and it gives the same error, and it gives the error on both domain and local accounts. I use Frontmotion Firefox as the browser. The network uses a squid proxy on a ubuntu box with dansguardian as a content filter. Other machines on the same domain with the same proxy settings are able to watch DRM protected content.