Money Plus 2008 is a US version and, as you probably know, will not open a file created with the French Money 2003 version.
You need to do a qif export of your data and import it into Money Plus sunset. There is a very good guide to the process here:
http://money.mvps.org/faq/importexport.aspx
and specific instructions on qif export/import here:
http://money.mvps.org/faq/article/28.aspx
Post back if you have a specific question or need more help. Also, let us know if this guide is helpful and works for you.
Bill Becker