Can anyone tell me what is wrong with the following formula..

=SUMPRODUCT(('Supplies DO - STPs'!A4:A7'Supplies Weekly'!A3)*('Supplies DO
- STPs'!A4:A7<'Supplies Weekly'!A3+6)*('Supplies DO - STPs'!C4:C7=Data!F5))

Here is the data it should be looking at.

date entry type
06/06/2006 DO Book
12/06/2006 DO Book
13/06/2006 DO Book
11/06/2006 DO Book


Thanks andy