In the second shot your camera has trouble focusing. Maybe you had too little light for it to succesfully focus.

It may also be motion blur.

I've seen you use ISO mode a lot, try changing it to Aperture mode and let the camera choose the sensitivity and shutter speed. But keep the camera steady! If possible, get one of these and use a timer to shoot the photo, for added stability.

The most flexible way to shoot is to eventually move out of all auto modes and into manually setting all three variables: shutterspeed (seconds and fractions of), aperture (F-stops) and sensor sensitivity (ISO-values).

I may be giving some pointers on these later, I'm thinking of writing a post about it.