\documentclass{minimal}
\usepackage{ifthen}
\nofiles
\begin{document}
\newif\iferror
\makeatletter
\ifx\@undefined\languagename
  \typeout{^^JThe command \string\languagename\space is undefined.}
  \errortrue
\else
  \ifthenelse{\not\equal{\languagename}{nohyphenation}}{%
    \errortrue
    \typeout{^^JThe language that is returned by
      \string\languagename\space is: ``\languagename''}
    }{}
\fi
\makeatother
\iferror
  \typeout{This fact causes isodate.sty not to work without the usage
    of either^^Jbabel.sty, german.sty, or french.sty.}
  \typeout{If you normaly use LaTeX without one of these packages do
    this:}
  \typeout{  \string\usepackage[american]{babel}}
  \typeout{  \string\usepackage[...,american]{isodate}}
  \typeout{The part ``...'' stands for one of the options num, iso, short,
    orig, TeX.^^J}
  \typeout{Please send an email to h.harders@tu-bs.de containing the
    file ``\jobname.log''!^^J}
\else
  \typeout{^^JOK. isodate.sty should work on your computer with or
    without^^Jbabel.sty, german.sty, and ngerman.sty.^^J}
\fi
\end{document}
