Fatal error: Class PHPExcel_Reader_excel2007 not found in IOFactory.php

Problem:

While working with PHPExcel you can get the following error:
Fatal error: Class 'PHPExcel_Reader_excel2007' not found in IOFactory.php

Solution:

The main reason is you are using "excel2007" or "excel5"
You need to use "Excel2007" or "Excel5" instead of "excel2007" or "excel5"
Please not that difference between "e" and "E".

Example:

Use as below:
$objReader = PHPExcel_IOFactory::createReader('Excel2007');//Excel2007 or Excel5