Issues uploading CodeIgniter from localhost to website

What version of CI that you use? I use the latest CI version 1.7.2 and in file system/codeigniter/Common.php I cannot find any call to CI_Hooks class.

Do you have custom library, or touch CI system file when developing? Have you verified that all files uploaded successfully to the server?

I had a similar problem a few months back and, unfortunately, never really identified exactly what happened. However the steps I took were the following:

Instead of uploading files and risking corruption in transfer just WGET the codeigniter zip file right to your server.

wget http://codeigniter.com/download.php

Unzip that file and then move it into your website root directory.

Now load your domain and make sure that the base CI installation is functional without ANY modifications. If that works then move your website specific files over a bit at a time and keep reloading often so you know what breaks (if anything).

In my case nothing broke so I can only assume that either SFTP was borking my files or that some other odd problem had occurred.

The loading of the 'Hooks' class happens in CodeIgniter.php on like 82. I would image that this is either an .htaccess issue of some kind, or maybe the path to your system folder is wrong.