Hi there,
Normally, the Wii remote will work properly unless dropped on the floor or banged against any hard surface. The Sensor connected to your Wii can sometimes end up dying because of normal use. This can be purchased for a mear 10 dollars at any Wal-Mart. If the sensor is not the problem, make sur that you are at the same level as your sensor when playing games. If you happen to be higher or lower, your Wii remote may end up moving unvolantarily around for no reason. The Wii remote is sturdy and has never broken up for me for the past 2 ½ years. Does the problem arise only when you use the docking station battery? If so, the battery would be the problem. I have stopped using this battery because of problems like these. I would recommend recharable Ni-hM batteries instead.
Hope this helps,
Regards