how to parse a .xlsx file in codeigniter

[eluser]Unknown[/eluser]
can anyone help me to read data from a .xlsx file from a specific folder using codeigniter PHP. i have go through the steps written here http://albertech.net/2010/04/codeigniter...cel-files/ using Excel Reader library but things doesn't work instead giving an error...

A PHP Error was encountered

Severity: Warning

Message: Cannot modify header information - headers already sent by (output started at D:\xampp\htdocs\dss\ci\application\libraries\Excel_reader.php:628)

Filename: core/Common.php

Line Number: 442


don't know why, please help, and thanks in advance.

and please suggest if there is any better approach other than this.