Refer information not received or incorrect.

Are you running Norton Internet Security?
Norton is a popular software known for blocking this information. If that is something you're running, click here on how to set it to make sure it sends our site the information it needs:
http://online.csudh.edu/support/kb/nis.htm.

In the name, url for the site you would enter www.thenewsvault.com, www.thedownloadvault.com, www.tvshark.com and www.tvshark.net (as four separate entries).

Are you running other third-party software?
If that doesn't ring a bell, have a look at any third party software such as firewall or privacy protector you may be running. You'll need to check the options and disable an entry similar to 'block referer' to fix this.