Statistics page not working

[hendry]

When a user clicks the webstatistics in de control panel the webpage that is beining opened is http://domainname.xxx/stats/ . This is not being recognized by Apache because the website is running under http://www.domainname.xxx . When opening manually the page http://www.domainname.xxx/stats/ everything is working fine. So my question is why is the controlpanel not using the www subdomain for the statistics?