When I double click on an Excel file to open it, I get a series of messages
that files can not be found as follows:

Personal.xls is locked€¦
C:\My.xls cannot be found€¦.
C:\Documents.xls cannot be found€¦.
C:\Documents.xls cannot be found€¦.
C:\and.xls cannot be found€¦.
C:\Settings.xls cannot be found€¦.etc.

It seems to be trying to open each word in the directory path as a separate
file. The separation seems to occur whenever it reaches a space or a slash
in the file path. This only happens with Excel files. All other files work
normally. Opening the file in Excel using the menu file/open€¦. works
normally.

Any ideas what could be causing this?

(Windows XP SP2, Office 2003)