Bill had to go through surgery due to the health problem, that was keeping him from singing, a cyst on his vocal cords that is. The surgery went very well, and Bill is recovering, but he isn't allowed to speak for some time, so the European 1000 Hotels tour, as well as the North American tour were cancelled.
Articles about Bill's condition could be found in various articles, mostly coming from Tom's declaration. You can find the articles, as well as a letter from Tom on the
forum.