I am trying to get the following formula to work:

=SUMPRODUCT((--([Detail.xls]sales!$B:$B,A2),--([Detail.xls]sales!$K:$K0),--([Detail.xls]sales!$K:$K<31),[Detail.xls]sales!$N:$N)

On the "sales" tab col B is a salesperson, Col K is a number value and
column N is also a number value and is what I'd like to calculate if the
conditions identified for A and K match . . .

Column K is the kicker - the conditions I'm seeking for Column K is that it
be greater than zero but less than 31. What's wrong with the formula above?

Thanks!!