I'd first start with the other troubleshooting methods in the other answers, with checking the battery. However is seems like this error is often times caused by a bad shutter and there is a fair chance the shutter assembly will need to be replaced.
Definitely rule out any other possible causes first, but if it is deemed the shutter is the cause, you can use [guide|180760|this guide] to replace the shutter assembly. It's not the easiest repair to do, as it involves disassembling the majority of the camera (including the image sensor), but it is doable.