You are right, that is a bug. King and Rook vs King is a basic end game in which the King and Rook will win. Instead of Kf6 the best move would have been 62) Rb7 if 62) ... Ke8 63) Rb8# or to prolong the mate 62) ... Kg8 63) Kf6 Kh8 64) Kg6 Kg8 65) Rb8#. Move 62 with the Rook is called a zwischenzug a German term that means in-between move. This forces the black king to put himself in opposition, and will give white the win.
this is what it said:
http://img221.imageshack.us/img221/2038/naamlooszp2.jpg
Anyways i should be happy with this draw given the fact that i was out of time, i moved like 5 times on the last second.