For some reason the
--(Input!$K$2:$K$1000=$J$18),
Criteria doesn't work?

I've used the following formula:

=SUMPRODUCT(--(Input!$G$2:$G$1000=$J$19),--(Input!$K$2:$K$1000=$J$18),--(Input!$A$2:$A$1000=A21)*Input!$E$2:$E$1000)

Could it be that the cells in Input!K2:K1000 column have formulas in them?

Help Please?