PHPOffice/PHPExcel — pull request #338 by kernel64 (2014-03-14 10:04:47+00:00)
Title: TO FIX BUG INDEX WITH MATH = #N/A

for exemple: =INDEX(C:C, MATCH(1,(A:A=M1)*(B:B=N1),0),0)
if Match return N/A, INDEX will return $arrayValues

To fix this I suggeste to return the ERROR code.