I was eager to see what Microsoft has done with reports in new SharePoint. But when I tried to enable and see these reports, I got an error 403 saying this page is forbidden. (I’m SharePoint administrator.)
This problem is known and is explained here: http://support.microsoft.com/kb/913384.
The article references a patch for solving this problem. I downloaded it but the problem was still present.
The workaround solution is described here by Matthew McDermott: http://mindsharpblogs.com/matthew/archive/2007/01/27/1506.aspx
To fix it: log in to your SharePoint Central Administration page with the account that is running your SharePoint application pool. This is the only account that will allow you to enable „Enable advanced usage analysis processing”.
The usage reports can be found on Site Settings for your site collection.