having problem charging battery . sign just shows a cross on it.the lead shows green and will not go to orange,hence it is just working off the mains.Bought new battery, worked for10 days now having same problem.
You could try resetting the logic board by unplugging your macbook, taking the battery out, and then holding the power button down for 5-10 seconds. That fixed my problem when my battery wouldn't charge.
There is a known issue with batteries not working. As long as your macbook is under applecare apple will send you a new battery, you'll just have to use the box they supply you to return the faulty battery.