Column A has dates
Column B has dates

I need to count the number of times that there is an entry in column B
within a date range (I am looking to do this by quarter) and an entry in
column A within that same date range. The data needs to be imbedded into the
formula rather than a seperate control cell. I have tried the following
formula but am not getting the right answer:

=SUMPRODUCT(--(A10:A40<4/1/6),(--(B10:B40<4/1/6)))

The answer to by formula should be 2 but this is producing 24. Note that
the data is on another worksheet.

Thanks!