It's a standard Petroff after move 4 except black still has a pawn on e7. Either he felt insulted by Alekhine's defense or he just played Nf3 automatically (possibly after checking that Black didn't play d5).
He played over 2000 games in four months according to Wikipedia. Maybe he was tired or something. It wasn't the only game he played badly:
http://www.chessgames.com/perl/chessgame?gid=1255142 (there's a third game in the comments).
