This is all guessing but from my limited research error 99 seems to come up when something tries to draw more power (milliamps) than it design rating SO look at the EXIF for the shots taken in the dark. Has the camera tried to close down the lens or is it shooting wide open? Do you have another battery? A weak battery can't deliver full power even though it's charged according to the ready light on the charger. A weak battery may be able to diliver the right number of milliamps but at too low a voltage to have the needed power to operate an electromechanical component. Amps X Volts = Watts. If one's low it will lower the amount of available power below the needed value.
If the battery is good AND you're limited to shots taken wide open ONLY it maY in fact be a lens problem BUT that's still a guess. Do you have another lens to try & does it get the same error? If so it's camera or battery related & something seems to be drawing too much power.
"A skill is developed through constant practice with a passion to improve, not bought."
