Unfortunately, I was met with this message: It looks like Netflix has been deactivated on this device. It could be an issue with your account or perhaps your device was deactivated on netflix.com. (2004)
I logged out and back into Netflix and was met with the same notice when attempting to play a movie. Uninstalling and reinstalling the app was met with no success, and finally I went onto Netflix's site to check and see if anything was afoot with my account. Everything was fine. I read in one spot that Netflix is limited to eight devices that can be authroized to it and thought that perhaps I had run that up at each ROM I flashed, but that was not the case either.
The solution for me ended up being Menu > Settings > Manage applications > Netflix > Clear data. Maybe this will work for you too.