I went to Reports Classic and under the Site Management Reports folder tried to access the Web Usage Reports and Raw Web Logs. When I do so a popup says "A username and password are being requested..." but nothing I enter in the username and password fields is accepted.
The username and password for these tools is on the Reports Classic page between the menus and tabs at the top and the the list of reports in the main of the page. You will see the following message:
Important information to access Web Usage Reports
When prompted for a user name and password enter the following: