I am trying to calculate the number of instances by employee

A18 = emplyee number
column c contains range of employee numbers
column I = contains the range of information that needs to be counted
a21=criteria listed within the range in column i

=SUMPRODUCT('Dec03-Dec30'!$C$2:$C$5500=$A$18)*('Dec03-Dec30'!$I$2:$I$5500=A21)*('Dec03-Dec30'!$I$2:$I$5500)

Why won't the formula above work.

Please and Thanks