Error: AWStats database directory defined in config file by 'DirData' parameter (/space/nas00/pro/http/sites/R/E/relais-de-monseret.com/data) does not exist or is not writable.

Setup ('/etc/awstats/awstats.relais-de-montseret.com.conf' file, web server or permissions) may be wrong.
Check config file, permissions and AWStats documentation (in 'docs' directory).