My Iphone reads Charging is not supported with this accessory. Why?

IPhone 4: This has been going on when I put in the original charger (the charger and head that came with the phone), also. I tried changing chargers and switching charger heads but every once in a while, the mesage will still pop up.

That isn't good. Take it to an apple store so they can check out whether it's your device or the charger.

The charger might be corrupted, try another one with a USB connection and hook it up to your computer.