Yeah, I noticed it went down a while ago. A LOT of people on that forum had been discussing not only leaked songs, but the entire new album, which is obviously not out legally. And I think some of the people were giving it out through the forum. So I guess Opeth or Roadrunner just decided they had had enough, and closed the whole Forum.
I read about it on BWBK.com several days after I noticed it was down.
Supposedly after the album is released, it will be opened again, guess we'll see.