Charging Problem

I've have two 3rd Gen iPods. Neither one will accept a charge using a dock connector/USB 2 cord regardless if it is connected to an AC Adapter or the computer port. I've plugged them both in using a dock connector/firewire cable via the computer port and got them both charged enough to test and they will both connnect to iTunes now using the USB cable but still will not accept a charge.

Whats up with that????

Anyone?