My math:

26/52 * 25/51 * 24/50 = 0.11764706 or 1 in just a hair more than 8.5

This gives odds of 7.5 to 1 against your making your flop.

By my line of thinking, for every 17 bets you place, you will win twice. This means you will lose 15 bets. On the last two, you will win and be paid 8 to 1, making 16 bets, for a total profit of 1 bet.

However, I'm quite convinced I'm missing something, as Party Poker would be very foolish to offer this sort of bet.