I have the same problem .
"Object reference not set to an instance of an object."
I didn't have this problem when we called XLWorkbook on a SSRS 2008 Excel file but now i got the problem when we upgraded SQL 2014.
"Object reference not set to an instance of an object."
I didn't have this problem when we called XLWorkbook on a SSRS 2008 Excel file but now i got the problem when we upgraded SQL 2014.