Flopped set becomes low flush

[HomerJay]

Nothing exciting about this hand, decided to play slow since I had to 2 flush cards to take away from villain's outs. After folding river, I began to think his psb was steal attempt following weakish (probe?) turn bet. Any thoughts?
PokerStars Pot-Limit Omaha High, $1.00 BB (6 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: 2+2 Forums)

Hero ($102.50)
Button ($57.10)
SB ($143.50)
BB ($109.85)
UTG ($224)
MP ($73.40)

Preflop: Hero is CO with A[img]/images/graemlins/club.gif[/img], 7[img]/images/graemlins/club.gif[/img], 7[img]/images/graemlins/heart.gif[/img], 6[img]/images/graemlins/heart.gif[/img].
<font color="#666666">2 folds</font>, Hero calls $1, <font color="#666666">2 folds</font>, BB checks.

Flop: ($2.50) 7[img]/images/graemlins/diamond.gif[/img], 2[img]/images/graemlins/heart.gif[/img], 4[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">BB bets $2.4</font>, Hero calls $2.40.

Turn: ($7.30) T[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">BB bets $4</font>, Hero calls $4.

River: ($15.30) Q[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">BB bets $14.6</font>, Hero folds.

Final Pot: $29.90