Excel reporting locked files but person does not exist

Using Active Directory, MS clustered file server, Office 2003

When a group of users access the same file, of course they get a
message stating that
the file is locked by some other user and it usually gives the person's
name that has the
file locked. The exception is that when a particular user has the file
locked, it does not
give that person's name, it simply says 'Nursing'. Since the word
nursing does appear
anywhere in the user's active directory property ***, I was hoping
somebody could
tell me where excel is getting the data for the user who has the file
locked.

Thanks in advance,

John

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