AWStats / Advanced Web Statistics is a collection of Perl scripts. The script files have .pl as their extensions.
In order for it to work, you need make it so .pl is interpreted by Perl. Because this is not normally enabled by default, you will see 404 error or "Page Not Found".
To do enable .pl files to be interpreted as Perl scripts, go to the control panel, click Web Options, and then on the CGI Extension - click add and enter .pl then click submit.