Sound duration: 0.0 seconds
Well, there you have the reason as to why you don't hear anything.
Now, I'm pretty sure that your sound is not actually 0 seconds long, so something is probably wrong with the file. I think have made the experience myself that SFML (or to be more exact: libsndfile) does not support all WAV formats, however, I cannot find a reference right now.
Do you know exactly what format your WAV file is in? If not, could you upload it?
EDIT:
Little update, the libsndfile website lists the supported formats. Not sure how I didn't find it earlier:
http://www.mega-nerd.com/libsndfile/