If you are trying to play videos on a Roku device, and the error message "HDCP unauthorized. Content disabled" appears, then you must go in to the main Settings in Roku, go to Devices, and set the resolution in Roku to match what your TV has (720p or 1080p).
We have also discovered that sometimes you have go to your Roku Settings, go to Devices, and set the TV resolution from the 1080p to 720p, and then back 1080p.
Some Roku owners are discovering that it might be a bad HDMI cable they are using, and others believe it is a recent firmware update by Roku. http://forums.roku.com/viewtopic.php?t=54968&start=0