( ! ) Notice: Use of undefined constant PHPEXCEL_ROOT - assumed 'PHPEXCEL_ROOT' in C:\wamp64\www\libs\phpoffice\PHPExcel\Autoloader.php on line 77
Call Stack
#	Time	Memory	Function	Location
1	0.0022	243320	{main}( )	...\Autoloader.php:0
2	0.0023	244152	spl_autoload_call ( )	...\Autoloader.php:36
3	0.0023	244256	PHPExcel_Autoloader::Load( )	...\Autoloader.php:36

( ! ) Fatal error: Class 'PHPExcel_Shared_String' not found in C:\wamp64\www\libs\phpoffice\PHPExcel\Autoloader.php on line 36
Call Stack
#	Time	Memory	Function	Location
1	0.0022	243320	{main}( )	...\Autoloader.php:0