Sumproduct & date trouble

[wildwally]

What would cause a sumproduct to return a value error? Here is my formula:

=SUMPRODUCT(--(YEAR(data!$N$2:$N$10000)=$K$1),--(data!$C$2:$C$10000=A3)+0)

I have been succesful in making this work on other pages, but when bringing it to my new book and changing the page and columns I keep getting a value error.

Any help would be greatly appreciated.

 

[onlyadrafter]

Hello,

I have managed to get #VALUE by having text in col N