As tag "office-word-itpro" focus more on general issues of Word client, but your issue is more realted to Word development.
To better help you, I would sugget you psot new threads on the forums mentioned by following link.
Word add-ins developer community
Thanks for your understanding.
Besides, I find an article "Excel launch error - 800700c1 is not a valid Win32 application", please check the solution "Deleting the file "C:\Program" is helpful.
Hope the information could be helpful.
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