Symptom: The flashlight display "Charging Error" message when the buyer is trying to charge the batteries
Possible causes:
1. Batteries are not making contact. Ask the buyer which brand/type of batteries he is using, are they "flat top" or "button top"
2. Flashlight is defective - if the light worked before, but it has "charging error" message now, it is a defective light and needs to be sent back for warranty service.