55 bottom set gets put all-in, my action?

[Dommer]

Villain in this hand is a loose-aggressive/passive, 30.6/9.9/.9, and he wins about 62% of his showdowns. He has gone to showdown 37% though. I only have 100 hands on him. I believe I've seen him make some moves but nothing like this hand comes to mind.

I figure his range is probably 88-77, 64, 96, 87, or a6s, I really can't imagine hes bluffing here but maybe. Does anyone call here or is this a good fold?

Party Poker No-Limit Hold'em, $ BB (9 handed) FTR converter on zerodivide.cx

UTG ($166.40)
UTG+1 ($99.16)
MP1 ($100)
MP2 ($90.40)
MP3 ($114.10)
Hero ($99.50)
Button ($89.70)
SB ($88)
BB ($99)

Preflop: Hero is CO with 5[img]/images/graemlins/club.gif[/img], 5[img]/images/graemlins/heart.gif[/img]. SB posts a blind of $0.50.
<font color="#666666">2 folds</font>, MP1 calls $1, MP2 calls $1, MP3 calls $1, Hero calls $1, <font color="#666666">1 fold</font>, SB (poster) completes, BB checks.

Flop: ($6) 8[img]/images/graemlins/spade.gif[/img], 7[img]/images/graemlins/spade.gif[/img], 5[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(6 players)</font>
SB checks, BB checks, <font color="#CC3333">MP1 bets $5</font>, MP2 folds, MP3 folds, <font color="#CC3333">Hero raises to $15</font>, SB calls $87 (All-In), BB folds, MP1 folds, Hero folds.

Final Pot: $113