What do you mean by "normal www" domain? There is no difference between domain names such as:
http://www.dogs.com/
http://greatdane.dogs.com/
or
http://www.greatdane.dogs.animals.com
The "http://" specifies the protocol to be used for the request, defaulting to port 80 for http "get" requests. The rest are just domains and sub-domains for the DNS to resolve the IP address to send the request to.
The "www" in a domain name has no more significance than the "greatdane"; both are just the authoritative, lowest level domains whose DNS should return the IP address for the page you want.
If the include stopped working, chances are that the URL you are referencing is no longer valid. Try keying it into the location field of your browser to see.
-- Rich