Hi! Very difficult to help with this long message and without seeing the problem itself. But try to search for it, check the links below.

https://docs.microsoft.com/en-us/answers/questions/258475/unable-to-cast-com-object-of-type-39microsoftoffic.html

https://stackoverflow.com/questions/28066719/unable-to-cast-com-object-of-type-microsoft-office-interop-excel-applicationcla