A problem from Harrington on Holdem

I'm reading Harrington on Holdem at the moment and I've noticed a strange comment on one hand. This is how it goes:

Early in a SNG, I'm in the BB, 2 callers in late possition, I have A [img]/images/graemlins/club.gif[/img] J [img]/images/graemlins/heart.gif[/img] and raise to 100 (with 10/20 blinds) and I get one caller (one seat before the button) and the rest folds

Flop comes 9 [img]/images/graemlins/diamond.gif[/img] 7 [img]/images/graemlins/spade.gif[/img] 3 [img]/images/graemlins/diamond.gif[/img]

Now Harrington suggests betting about 150 as the pot was 260. But I bet 100 instead of it and opponent calls.

Turn card is 6 [img]/images/graemlins/club.gif[/img]

Both players check.

On the river Q [img]/images/graemlins/heart.gif[/img] comes.

I check opponent bets 100 and I call. Villain shows K [img]/images/graemlins/diamond.gif[/img] Q [img]/images/graemlins/diamond.gif[/img]

Nothing strange in these hand and I read Harrington's comment on it. He says (if it's illegal to quote someone's book then I'll correct it): "You were a bit unlucky, since he shouldn't have called your bet after the flop - there were just too many ways he could have been beaten."

I don't consider myself as a very good player and I can be wrong but this comment seems to be quite strange. On the flop the pot was 260, I bet 100 so opponent is getting 3.6-1 pot odds so how calling with a sceond nut flush draw and 2 overcards here is a mistake? Even if I bet 200, the pot odds would be around 2.3-1 and I'd consider villain's call in such situation as a correct. But as I said before I may be wrong so someone could please correct my thoughts? For those who have this book, the mentioned problem is on pages 292-294.