I agree that the problem is likely to be inadequate light for the autofocus to work.
I suggest:
1. Try selecting just 1 central autofocus point
2. Increase the light in the room
3. Fit a Speedlite flash with an infra-red AF assist beam. This is great for focusing at night in general.
4. Enlarge the image to 10x by pressing (twice) the button with a + in a magnifying glass and focus manually