Sumproduct from date range

Hi All,
Back for some more guidance from the gurus. I have the formulas below but want to add in 2 date cells from another sheet within the same workbook but when I try I keep getting errors!!


=SUMPRODUCT(('ACTION PLAN'!E13:E1000="PT")*('ACTION PLAN'!I13:I1000="OPS"))

I would also need to change the part below that refrences a date as this will be changed by the user in from and to date cells on the other sheet.

=SUMPRODUCT(--('ACTION PLAN'!E13:E1000="PT"),--('ACTION PLAN'!I13:I1000="OPS"),--('ACTION PLAN'!M13:M1000>"04/01/2009"+0)*ISNUMBER('ACTION PLAN'!M13:M1000))

Many thanks,

Something like:

=SUMPRODUCT(--('ACTION PLAN'!E13:E1000="PT"),--('ACTION PLAN'!I13:I1000="OPS"),--('ACTION PLAN'!M13:M1000>'Other Sheet'!$X$1),--ISNUMBER('ACTION PLAN'!M13:M1000))

where 'Other Sheet'!$X$1 is the location of the Start date.... if you want to add a to date:

=SUMPRODUCT(--('ACTION PLAN'!E13:E1000="PT"),--('ACTION PLAN'!I13:I1000="OPS"),--('ACTION PLAN'!M13:M1000>'Other Sheet'!$X$1),--('ACTION PLAN'!M13:M1000<'Other Sheet'!$Y$1),--ISNUMBER('ACTION PLAN'!M13:M1000))

where 'Other Sheet'!$Y$1 contains end date.

Note: the search will not actually include those dates in the cells... if you want to include, then you need to change < to <= and > to >=