SUMIF #VALUE error b/w 2 workbooks

[apiekar]

Hello,

I am having the strangest problem and hope someone can figure it out for me.

I am using a SUMIF formula to calculate a particular value from a different workbook. To create the formula I open up both workbooks (the one w/ the formula and the one I'm pulling the numbers from) and create the formula with no problem. The correct value appears and everything seems like it's working fine.

However, if I save and close out of both workbooks, and then open up only the workbook with the formula, excel asks me if I would like to update the links to other data sources. If I click update, the cell w/ the SUMIF formula changes to #VALUE (error).

But... if I then open up the workbook that the formula is linked to, the cell changes back to the correct numerical value.

What I need is for the workbook to be able to hold the correct numerical value, after updating the links, without having to keep the other workbook open.

Any ideas?

Thanks

[apiekar]

=SUMIF('[Dstar - gRAMP+gIP AP.xls]Sheet1'!$A$5:$A$560,$A$1,'[Dstar - gRAMP+gIP AP.xls]Sheet1'!$F$5:$F$560)

FYI here is the formula