This looks like the normal definition for \tableofcontents except instead of using \contentsname the title for the table of contents is hard coded.  The default French babel setting only captializes the first word.  A better solution is to replace the code identified by Tom with:

\renewcommand{\contentsname}{Tables des Mati\`{e}res}

However, after trying this I notice that the document includes svmult2e.sty that doesn't use \contentsname.  So Tom's suggestion of creating a new package file is necessary.  See the last section at http://www.mackichan.com/techtalk/419.htm for some additional information.

SW does try to expand macros defined in the document preamble and this particular macro expansion causes a problem.  Version 5.5 doesn't crash, but it also doesn't open the document.