[Sumif] for multiple tabs

Hi,

I'm trying to do a sumif function on the multiple tabs.
For example, I have 50 standardized tabs for each state, and they need to be
group by certain criteria. But when I try to do
=sumif(AL:WY!D,A1,AL:WY!N:N), I'm getting an error message. Column D is the
criteria and column N is the number.
I know that similar formula works on the regular [sum] function, but not for
[sumif]???

Please help.


Stan