Motorola E815 / E816 Hollywood

For a while now, I've been having trouble charging my e815 at home. When I plug it into the home charger, it says "unable to charge"? The same charger will charge my other moto phone and headset with no problem, so I know its not the charger. I have taken it to the verizon store and they say that it charges fine...but it doesn't. I tried a new battery and it made no difference. The weird thing is that at times it will charge, but other times it gives me the "unable to charge" error. what gives??