#2. "RE: Newbie Question - Shutter Release Disabled" In response to In response to 0
I don't have any experience with a D3100; However, I would do what the error message says, and recharge the battery. Then continue to use the camera, and see if it happens again. You should probably try to see if the camera is faulty first, but I recommend always having a backup battery.
Hopefully, others will be familiar with this particular problem.