A couple of weeks ago the Microsoft updater installed Service Pack 3 (SP3) for MS Office 2003 on my machine. Great, more bugs fixed.
It appears that MS blocked some older file formats from being read/written 'because of security reasons'. Lotus 123 formats were included too.
I don't know about you, but I still use WK3 files rather regularly for importing data quickly into Notes. I discovered Microsoft had a document written to solve the issue by manually tweaking the Registry. 2 days ago they admitted having made a mistake, and updated this page, by adding .reg files to 'fix' the registry much easier. So if you have SP3 installed and want WK3 support back for Excel,
run the following .reg file: UnblockExcel.reg

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