The control panel we use (HELM) has an option in the admin section to switch off reporting on log files which is handy.
AWStats creates it's own log files out of the IIS log files when it parses them in. These usually get stored at awstats\data\ and there is a file each month for each domain on the system that uses it. If these files get deleted and you have deleted the IIS log files then you are stuck and cannot reimport them... so keep that directory backed up well 