Wii Remote buttons are not responding or are responding incorrectly.

If you are using a Wii console with model number RVL 001, check the GameCube Controller sockets to see if anything is attached to the console. If an accessory has been left plugged in, the console may be looking for input from that accessory instead of from the Wii Remote or Classic Controller.
Clear the syncs on the console.
Try a new set of batteries. Sometimes weak batteries can cause these types of problems to occur.
Reset the Wii Remote.
Make sure there aren't any other buttons being pressed. For example, the B Button might be held down on the bottom of the Wii Remote, the Wii Remote Jacket may be misaligned and pressing buttons down, etc.