public int XlsxToXls(
	string fileXlsx,
	string fileXls
)

Public Function XlsxToXls ( _
	fileXlsx As String, _
	fileXls As String _
) As Integer

Return Value

0 - Ok.

1 - Can't open source file. Check input file.

2 - Can't create the destination XLS file. Check the permit for destination path.