How can I resolve a shutter release button problem with a Nikon D5100? I dropped the camera on the floor and now it displays "Error: press shutter release button again."
Try swapping the battery. If that didn't work the shutter may be jammed in which case you should really take it to be serviced. (You can probably free up the shutter yourself but you risk breaking the camera worse. I had this happen on my D5100 and I was able to free the shutter with a gentle pry done with folder up paper... but I really don't recommend this technique as you can totally destroy the camera.)