Can anyone help me understand the differences in the way that Internet
Explorer 7 handles Excel files?

Our company intranet links to several Excel files. When a user clicks the
link, they get a warning from Excel that the file could not be found. The
warning is:

"<file path could not be found. Check the spelling of the file name, and
verify that the file location is correct.
If you are trying to open the file from your list of most recently used
files on the File menu, make sure that the file has not been renamed, moved,
or deleted."

The file name and path is correct (I've triple checked). We have tried on
multiple systems with different setups. The thread is that when a user with
IE7 or 8 running Office 2000 opens the file, they get the warning. If they
use IE6 and Office 2000, they don't get the warning. If they use IE7 or 8
and Office 2003, they don't get the warning.

I am absolutely stumped as to what might be causing this problem. Any
suggestions, however obscure, would be greatly appreciated.