Issue with AWStats and IIS Web Service Extension

I'm trying to get AWStats to work but I'm having an issue. I'm getting page not found but I know, sort of, what's causing it. I believe it's related to the right executable being allowed in the extensions. I have the perl.exe allowed but it does not work. If I turn on "all unknown CGI extensions" it works. So something must be missing. 

In past we face pretty same issue which was resolved using this kb info http://portal.hostingcontroller.com/KB/a18/how-to-fix-awstats-statistic-server-update-issue.aspx

Thanks. i was trying to avoid allowing unknown CGI extensions but I guess it's not a huge deal. I'm all set. Thanks!