I managed to get the cms working on the server with php 5.3. The errors i was seeing prior have been cleared accept for one. But if possible I will like to add some information to the installation doc. It took a lot of tweaking to get the initial page to load properly.
1) The htaccess file caused 500 error when suphp is installed because the php_value/flag directives are not supported.
2) The RewriteBase is set to / by default , keeping this with this value returns a white page with Welcome to hostname. I installed this into a subfolder so i needed to modify the / with /subfolder_name . The page then loaded up
3) nothing int he admin area works, all the links goes to 404 pages , The structure does populate , but i can not modify them. not sure if this is because i commented out php_flag allow_url_include On & php_flag allow_url_fopen On
4) Error on the main page
Severity: Notice
Message: Undefined variable: medias
Filename: Tagmanager/Page.php
Line Number: 1059
**** its a warning so i suppressed it for now by adding ~ on line 118 of the index.php file ( error_reporting(~E_ALL ) **
I am still studying your code as I am a lil new to CI .. but it would be nice once i get the admin area working ..