Here again,

I had a formula which looked up the qty of items a customer has ordered for
delivery within a month ie Jan, Feb etc

The formula was

=SUM((openorders!$V$2:$V$114=$C$3)*(openorders!$AD $2:$AD$114="Dec
08")*(openorders!$X$2:$X$114))

it looks at the part number on my summary sheet $C$3 against the part number
in col V in the open orders sheet. Then it looks at all the orders due out in
Dec and sums the total qty.

When the range goes larger than 114 rows, it will mean me having to
maintain all the formula's to extend the range, so I thought I could change
it to read the Last Row for each of the columns V, AD and X , so my formula
now looks like this

=SUM((openorders!$V$2&"_"&Row=$C$3)*(openorders!$A D$2&"_"&Row="Dec
08")*(openorders!$X$2&"_"&Row))

Unfortunately this gives me a #NAME error.

What have I done wrong.
Thanks
Winnie