Update your version of Excel or change:
#"Added Index" = Table.AddIndexColumn(#"Promoted Headers", "Index", 0, 1, Int64.Type)
to:
#"Added Index" = Table.AddIndexColumn(#"Promoted Headers", "Index", 0, 1)
The same will apply to step Added Index (step 15 or so) of Result query:
= Table.AddIndexColumn(#"Removed Columns2", "Serial Number", 1, 1, Int64.Type)
becomes:
= Table.AddIndexColumn(#"Removed Columns2", "Serial Number", 1, 1)