It is impossible to use 'S' column specification with current set of packages from dev-texlive/*. latex reports a lot of "! Undefined control sequence." errors. Siunitx author clarified this as version incompatibility (e.g., http://tex.stackexchange.com/questions/67680/siunitx-not-working-in-table). Current siunitx.sty from CTAN works fine with dev-texlive/texlive-latexrecommended-2012.
indeed, i've updated siunitx in tl-science-2012-r1 which should fix the problem thanks for the report!