Hello. My name is***** can assist you with your question.
This means what you probably already suspect – that the battery has failed door isn't charged for some reason. The icon with a line through it in any case means that the battery at least according to the device, is not charged. If you haven't done this already, I would try leaving it plugged into the computer overnight since the charging current from a computer is only 500 mA – it can take as long as 24 hours to charge a device completely. It's also possible that if the device discharged completely that the rechargeable battery will need to be replaced. If that's the case and you find that out after trying to recharge it for 24 hours, let me know and I'll see if I can find you a replacement battery. I'm not sure that the rechargeable battery in this devices supposed to be user replaceable but that doesn't mean we can't find one.