sumproduct error occur

[gingank]

i try to do a coding on the vba where my logic is is sheet1(a) = sheet2(a) & sheet1(no) <> sheet2(no)
Why i can get the error.
i try to do is match sheet1 = sheet2 (first condition) & sheet1 <> sheet2(second condition)
in the sumproduct. Could anyone help me on this ?
my coding is as below:-

If Evaluate("=sumproduct(--(sheet1!$a$1:$a$" & lastrow & "=B" & i & ") * (--(sheet1!$a$1:$a$" & lastrow & "=B" & i & "),--(sheet1!$c$1:$c$" & lastrow & "=I" & i & "))") = 0 Then

[martindwilson]

why have you 2 different last row parts ,if last row I is different from last row B then sum product will fail because thet have to be the same dimensions