Links come up as #Value for closed source workbooks

Hi there,

I am currently having an issue in Excel 2003, where links from closed workbooks on our network show up as #value. The formulas and links involved have not been changed, nor have the files been moved.

Here is an example of one of the formulas

=SUMIF('N:\Financial Controller\Management Accounts 2008\P1 Jul07\MPPL July 07\[TB MPPL Jul07.xls]TB'!B$19:B$586,D14,'N:\Financial Controller\Management Accounts 2008\P1 Jul07\MPPL July 07\[TB MPPL Jul07.xls]TB'!D$19:D$586)

This will not work unless the workbooks are open.

I looked around and found that SUMPRODUCT will work

here is an example of the same cell working with the different formula

=SUMPRODUCT(('n:\financial controller\Management Accounts 2008\P1 Jul07\MPPL July 07\[TB MPPL Jul07.xls]TB'!B$19:B$586=D14)+0,'n:\financial controller\Management Accounts 2008\P1 Jul07\MPPL July 07\[TB MPPL Jul07.xls]TB'!D$19:D$586)

The problem is we have a lot of workbooks with a lot of links. They have worked in the past and not all of the links are SUMIF, we have VLOOKUPS with network links in them also.

Does anyone know why this would have changed just recently (last 2 weeks)

Thanks and Regards,

Rob R