I can't find any Esif info to check your exposure settings for this shot.
Clicking on it takes me to a Yahoo! log-in page Also, I cannot
find it in your Photostream.

So, going on what you have here, and assuming it is not a cropped shot,
I'd say "too close for the aperture used". (Ie, the aperture can't yield an
acceptable DOF.)

So, depending on how well your camera handles high ISO, use a higher one
to allow a smaller aperture AND get a bit farther away from your subjects.
I'd guess that about 3x this apparent distance may have given you
better results.

You'd have to do a bit of trial-and-error, but that's about it.