PhpDig passes its user-agent on every request and does nothing to block referrer, so I wouldn't think this issue is related to PhpDig. Note that, in the following line, not even the page size is given. Perhaps send an email to server4you and see if they have an idea.
Code:
69.64.40.48 - - [12/Jan/2005:11:33:00 -0500] "HEAD /contact_us.php HTTP/1.1" 200 - "-" "-"