#REF! error when opening a workbook that contain a refference to another workbook

[tanababa]

Hi,
I have attached two files. Source and Calculation.
With in the Calculation file I have two reffernces to a cell that is in the Source workbook.



When using the table naming refference I get an error as soon as I update the workbook.
='C:\Users\Tamir\Dropbox\Source.xlsx'!Table1[[#Totals],[D]]

When using the relative form of refference I do not get the error
='C:\Users\Tamir\Dropbox\[Source.xlsx]Data Source'!J13

Why is that?
It is a crucial problem because I gae many emails with excel attachments without their source files.

Thank you,
Tamir