Use this formula instead:
=VLOOKUP(A2,Leases!A

,COLUMN(),FALSE)
EDIT: Damn smiley got in the way. Should be A : D w/o the spaces.
Note that it would be better for recalculation to narrow the A

range as right now you're forcing Excel to look through 65,536 x 2 rows.
Hope that helps,
Smitty