made mojong account (email adress as login name) pwd.

played the demo on minecraft.net

and found World of Minecraft site, downloaded client, and entered name/pwd

 but says, unable to autenticate ,you user name / password may be incorect

or no servers to validat your login.

in the World of Minecraft.exe there is a mc:// line, that is blank, must it be blank or what comes there.