HTTP Error 404. The requested resource is not found - occurs when a particular ip is used in the binding. IIS 7.5, win 7 ult.

I have a static content site that loads normally when "All unassigned" or 2 other virtual adapters on my pc is used in the binding. Whenever I select the main physical adapter's Ip, I get the "HTTP Error 404. The requested resource is not found". This adapter is the one used in my internal LAN and for internet access. I've added an entry in the hosts file: 172.16.4.3 localhost (host header) for this but still doesn't work. I need help in resolving this. Thanks.