我使用PHPexcel在CodeIgniter中读取Excel数据。 它在本地主机上工作正常。 每当我将其上传到实时服务器时，都会出现这样的错误消息。
遇到未捕获的异常
Type: Error
Message: Class 'PHPExcel_Worksheet_Protection' not found
Filename: /home/customer/www/mail.escaperoommarketer.com/public_html/application/third_party/PHPExcel/Worksheet.php
Line Number: 356
Backtrace:
File: /home/customer/www/mail.escaperoommarketer.com/public_html/application/third_party/PHPExcel.php
Line: 371
Function: __construct
File: /home/customer/www/mail.escaperoommarketer.com/public_html/application/libraries/Excel.php
Line: 8
Function: __construct
File: /home/customer/www/mail.escaperoommarketer.com/public_html/application/controllers/MainController.php
Line: 132
Function: library
File: /home/customer/www/mail.escaperoommarketer.com/public_html/application/controllers/MainController.php
Line: 106
Function: readExcel
File: /home/customer/www/mail.escaperoommarketer.com/public_html/index.php
Line: 315
Function: require_once
有人知道为什么会发生此错误，如何解决？
预先感谢