I suspect this is related to rt://48858. A quick web search shows some results suggesting which registry key to create (as suggested in that rt ticket), I don't work on Windows anymore, so you'd need to check.

Update: I think this should help find the GUID you need, if this one doesn't match what you have installed: c:\wmic product where "name like '%%Excel%%'". Hopefully a Windows person will turn up who can advise better.

Update 2: without knowing what you're doing in excel, this may not be appropriate, but I use Excel::Writer::XLSX to create xlsx files, without the need for the Excel program, or Windows.