Thank you for offering your insightful interpretation of your
vague recollection of what the error message might have said in
part. But you can better help us to help you by quoting exactly
and completely the error message you see on your screen, because
we can't see your screen from here.
If the error message says, "File <filename> is not available",
and if you're using Symantec/Norton AntiVirus, then try disabling
the Office Plugin that comes with Norton. See
http://support.microsoft.com/?kbid=329820 "How to use Office
programs with the Norton AntiVirus Office plug-in" for more
information.
If the error message in part says, "It may be on an unavailable
volume, or protected with a password", or something else, then
write back with the exact error message you see.