My guess is that you are plugging the device into the USB port on your keyboard. The message means that the device is trying to pull more power than that USB port has available. On older computers the keyboards did not support "full power" devices (and on the newer ones, only a single "full power" device).
The easiest solution would be to plug the charger into a USB port on the back of the computer. These are all "full power" ports, and each has enough juice for a device.
And there is no need to worry about damage. The USB spec has provisions for the devices to negotiate to the proper level, so they will not damage each other.