I have use this formula before, but i try it again on another sheet and now
it does not work.

This Works:
=SUMPRODUCT(('Dec Actual'!$F$2:$F$100="0103")*('Dec
Actual'!$G$2:$G$100=B101)*('Dec Actual'!$I$2:$I$100))

This does not:
=SUMPRODUCT(('Source'!A5:A350="A")*(Source'!B5:B35 0=A8)*('Source'!AM5:AM350))