Since the conversion to 2007 we have found that Excel is changing link
references for files with the same file name, but different paths.

A simplified example:
We have two files labeled "month-end stats.xls" in each a June 2007 and May
2007 folder. Our "Trend.xls" spreadsheet is linked to each of these
spreadsheets.

If I open the month-end stats file in the May 2007 folder, and then open the
Trend.xls file, ALL of the links will change to reference the opened file.
The links that were referencing the June 2007 data now reference the file in
the May 2007 folder. Once I close the month-end stats file, the full path of
the link is displayed and it clearly changed the path of the link to
reference the other file.

Because I work with many different files from different sources, combating
this problem by giving each and every file a unique name is not practical.
This problem did not occur in any earlier version of Excel and appears to be
more prone to happen when I have links in formulas (such as sumif) than with
simple cell references.

It has occurred multiple times and I can recreate it, so I know there has to
be an issue.