Warhammer 40K: Dark Millennium Online was not passed down by THQ itself, and these "facts," such as the launch date and class list, should be treated as speculative rumors and nothing more.
THQ sent a letter to several media outlets clarifying the situation:
It has come to THQ's attention that some media are reporting that we've announced game details and a release date for our upcoming massively multiplayer online project, Warhammer 40,000: Dark Millennium Online. At this time THQ has not officially announced a release date and any reported features are pure speculation. THQ will announce confirmed game features and an official release date at a later time.We will keep an eye on this title and the news coming out of THQ as it develops.