Thanks. I found the problem this morning when I looked at the formula with fresh eyes. I was missing a right parenthesis after the date portion of the formula. I stared at it for hours yesterday until the whole formula was blurry. It should have been:

=SUMPRODUCT(--('Spread Sheet'!$A$5:$A$5000 >=date(year($a$4),month(1),day(1))),--($A$5:$A$5000<=$A$4),'Spread Sheet'!$L$5:$L$5000)

instead of

=SUMPRODUCT(--('Spread Sheet'!$A$5:$A$5000 >=date(year($a$4),month(1),day(1)),--($A$5:$A$5000<=$A$4),'Spread Sheet'!$L$5:$L$5000)

Thanks again!

Opv