The DVDFatal error occurs when a Wii or GameCube has a fatal error when loading a disc that the console cannot recover from.
DVDFatal is the actual function called in the game code in this scenario.
When a DVDFatal happens on a Wii, an error with wording similar to, "An error has occurred. Press the Eject button, remove the Game Disc, and turn off the power to the console. Please refer to the Wii Operations Manual for help troubleshooting" will be presented on-screen. The only way to clear the error is to power off the console.