I have a workbook (Excel 2003) that is saved on a shared network drive, that
includes worksheet protection. The logic is that one person does updates to
this worksheet & then protects it with a password. Then others may open that
workbook & do a "Save As".

What is happening is that the password is somehow not working after some
time....can you provide some insight into why this might happen? This file
is maintained by only one person, so any copies that are made should include
the same data as the original because nobody else may edit the content.