Something happened and I could no longer watch videos on Netflix due to the above error (on a Windows 7, 64-bit machine). Googling, I discovered this is a Silverlight error. Tried uninstalling and reinstalling Silverlight, but that made no difference. Also tried deleting the file C:\ProgramData\Microsoft\PlayReady\mspr.hds as I had read in some guides, but that didn't solve the issue either. What finally worked was changing permissions on the following folder. I had to give my user full control. C:\ProgramData\Microsoft\PlayReady Before changing permissions, I would try reinstalling Silverlight and deleting mspr.hds first. But if that doesn't work for you, check the permissions on the PlayReady folder.