My website works only with www

[sdsh]

I am the administrator of the site "http://www.sdsh.co.cc" where I have installed wordpress. When I try to visit "http://sdsh.co.cc", I get co.cc's site saying that www.sdsh.co.cc is available for registration. When I open www.sdsh.co.cc, the blog works fine...

Is there any idea about the paradox? I have full DNS control provided by co.cc. Is there anything to play with it? Any help is appreciated.

Saeed