Fatal error: Uncaught Error: Call to a member function setActiveSheetIndex() on null in C:\Apache24\htdocs\PortalUIS_PruebasVUCEM\excel\hojaExcel.php:35 Stack trace: #0 {main} thrown in C:\Apache24\htdocs\PortalUIS_PruebasVUCEM\excel\hojaExcel.php on line 35