Theorem as stated is not true. The problem with the current proof is that an alternative 'incorrect' structure may share the skeleton of the true structure $G^*$. In this case, it is not true that .. Two weaker results do hold: 1. All results in the paper are correct, assuming that we replace the requirement of recovering the correct structre by recovering a graph which shares a skeleton of the correct strucutre. 2. All results in the paper are correct, provided that we change the definition of $IC_B$. Instead of the 'minimal information carried by an edge', it should be 'the minimal information lost by an edge flipped'. To see this, Thanks to Peter Spirtes, and David Sontag and Eliot Brenner for pointing the errors in the current version.