Alvin,

What operating system are you using?  If you are using Windows XP or 2000
this may be a limitation in your account with being able to read the
particular registry key or setting the registry key.

To find some more information on the registry key that may be giving you the
problem you can check out www.sysinternals.com and download the appropriate
Regmon for your OS.

1. When you start the application, stop the capturing and clear the buffer.
       If you have a shortcut on your desktop for Excel this is really easy
and you get very little in the regmon capture.  So you might want to create
one then perform the following items.
2.  Reduce the Regmon window so it is not a full Screen but just a window.
Launch Excel and do the same thing making it opposite in your screen from
Regmon.  Then close Excel.
3.  Start the capture in Regmon and launch Excel.  Once you get the error
stop Regmon before accepting the error.
4.  After accepting the error you can then return to Regmon and export the
data to a TXT file and load it in to Excel.  This will allow you to filter
the data using the AutoFilter function.  You should be able to see failures,
but you will need to check each failure to see that it is not second
chancing and finding the correct path or getting a success.

Professional support personel can help you with this process further if
needed.