WAMPServer 3 Create a Virtual Host -Problem (6 replies)

I have followed the steps as decribed in WAMPServer 3 Create a Virtual Host, the easy way"", but when I click on the virtual host created, the page is not displayed with the error "This page cannot be displayed". Reason: UNKNOWN
Notification: DNS_FAIL.

I also included this virtual host to my hosts file. What can the problem be.