I was performing sanity checks on mpich2 1.4.1 x64 Windows build and found that Nemesis tcp netmod hangs in MPI_Finalize() (Sounds like a bug that a user reported a week or so back. He was suggested to see if sock works.) . Using Nemesis shared memory OR sock channel works.
So my guess is that the problem existed from the previous version onwards.
Looking into this problem.
-Jayesh