Hi,

To be on the safe side and gain flexibility :

1. extract from formula the dates and place them in separate cells C2 and D2

2. add operator --

=SUMPRODUCT(('FY 2006'!A8:A550=C2)*('FY 2006'!A8:A550<=D2)*--('FY 2006'!B8:B550))

HTH
Cheers
Carim