Why A2 low is beaten by A3 in this hand (newbie)

[chalimac]

***** Hand History for Game 2750082977 *****
$0.50/$1 Omaha Hi/Lo - Wednesday, September 21, 11:47:58 EDT 2005
Table Table 39270 (Real Money)
Seat 8 is the button
Total number of players : 9
Seat 1: Synchroncity ( $30.62 )
Seat 2: storment ( $19.63 )
Seat 5: metalchair ( $18.20 )
Seat 10: suited28 ( $16.24 )
Seat 4: T_Librarian ( $35.94 )
Seat 7: YukonGoldy ( $32.63 )
Seat 8: Batman127 ( $17.36 )
Seat 3: jjmarks ( $9.50 )
Seat 6: TREVI ( $23.50 )
suited28 posts small blind [$0.25].
Synchroncity posts big blind [$0.50].
** Dealing down cards **
Dealt to T_Librarian [ 6s 2c Ac Ah ]
storment calls [$0.50].
jjmarks folds.
T_Librarian calls [$0.50].
metalchair folds.
TREVI folds.
YukonGoldy calls [$0.50].
Batman127 folds.
suited28 folds.
Synchroncity checks.
** Dealing Flop ** [ Js, 4h, As ]
Synchroncity checks.
storment checks.
T_Librarian bets [$0.50].
YukonGoldy calls [$0.50].
Synchroncity folds.
storment calls [$0.50].
** Dealing Turn ** [ 7s ]
storment checks.
T_Librarian bets [$1].
YukonGoldy raises [$2].
storment calls [$2].
T_Librarian calls [$1].
** Dealing River ** [ 8s ]
storment checks.
T_Librarian checks.
YukonGoldy bets [$1].
storment raises [$2].
T_Librarian calls [$2].
YukonGoldy calls [$1].
storment shows [ Ks, Qs, 9d, Jd ] a flush, ace high.
T_Librarian shows [ 6s, 2c, Ac, Ah ] three of a kind, aces.
T_Librarian shows 7,6,4,2,A for low.
YukonGoldy shows [ 4s, 5s, 4c, 3s ] a flush, ace high.
YukonGoldy shows 7,5,4,3,A for low.
storment wins $7.50 from the main pot with a flush, ace high with king kicker.
YukonGoldy wins Lo ($7.50) from the main pot with 7,5,4,3,A.