Brief details he http://www.rookhouse.com/forum/viewforum.php?f=16

Well, I predict this will be the end of the match. Kramnik wanted to
play Game 5 today and will no doubt walk out if the forfeit is upheld.
Meanwhile, I assume Topalov would walk if the forfeit was not upheld
(the 1972 Fischer-Spassky match sets the precedence that not showing up
results in a forfeit).

Sad...

John