It means you need to delete your user settings file and, unfortunately, build your settings again. I’m not sitting in front of Nuendo right now so I can’t tell you where the settings file is, but deleting it worked for me…
Another thing: You’re not running an older Nvidia Quadro graphics card by any chance, if you are, you may have to update the driver or even disable it while running Nuendo. There’s some issues with the Quadro that may also get you that error…