HTML Editor not showing correct modified date

I have started to have problems in not getting amended html files to show the
correct modified date.
The amended data is saved in the files but the files continue to show the
previous modified date.
The HTML editor I use is Coffee Cup Editor 2006, but trying First Page 2006
also fails to show the correct modified date.

Trying to pin down when the problem first started I suspect that it did so
since mid May. As I have all the latest critical automatic updates to my
system Windows XP Pro SP2, I wonder if one of the updates is causing the
problem.
Has anyone else experienced, or know of, this problem?
Thanks

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Bill L