If web traffic reports (AWStats or Webalizer) are no longer updating for a domain, it probably means the domain is locked for updates. This can happen in a case where a previous update terminated abnormally.
Before proceeding, make sure no instances of statistics.exe are currently running in the server's process table.
Through regedit, browse to the following key:
*Note: the value for DomainIds can be retrieved from the MySQL table psa.domains
Reset the value of OfflineLockStatus to 0 (zero) and re-run statistics for this domain via command-line.