SUMPRODUCT Error

I got 3 columns of data for ex
col f6:f19 is defect severity can be 1 or 2 or 3
col c6:c19 is defect status "Open" or "Closed"or "Pending"
col d6:d19 is age of defect . the data in column D is derived by a formula using today()-(g6:g19) . some data in column is hardcoded and some is not

I need to create a matrix to find out total defects status =Open, Sev = 1 or 2 or 3 and age = <10 days,<20 days,>30 days.

The problem i am facing is there is no data in some cells because status=closed.
I used this formula and this worked for only one or 2 cells where there is uniform data.

=SUMPRODUCT(F6:F19=3,C6:C19="Open",D6:D19<=10)

I get either 0 or #VALUE error . 0 is not correct and it should give me 4.

is there a way out if the data in underlying cells is not uniformly formatted?


Thanks