Odd, did you play g4 just as his time was expiring? A win on time works just as well as a checkmate though!
live chess - checkmate did not register

It was not checkmate -- black had the option of playing 34...hxg3 to remove the pawn on b4. This type of pawn capture is called "en-passant" which is french for "in passing." To explain quickly, when a pawn moves 2 squares forward the opposing player is allowed to capture it as if it had only moved one. This option is only available for the move immediately after.
http://en.wikipedia.org/wiki/En_passant

I would love to see the look on your face if your opponent new the en passant rule. I'm sure we would have saw a thread on how live chess allows cheating. LOL

Aw, give the guy a break. We were all new players at one time, and we all were surprised when we first learned the "secret moves" of castling and en passant.
I'm sorry, anshoogrover, you've just happened onto the Mean Kids' Playground, and they want your milk money.
The first time I learnt en passant, I was pretty suspicious that they would mock me later afterwards, for believing in such non-sense made up for their advantage. Luckily it turned to be true.
To be fair, only one comment was mean and childish among 4, imo. So it's just one mean kid lurking around in the supermarket.
http://www.chess.com/livechess/game.html?id=74700826
this is the link to the game i played - everytime a pawn checkmates a king - it does not register as a checkmate!