[eluser]Sheldon[/eluser]
Are you getting Errors or Notices/Warnings ?
In your CI index.php file, check the line that sets your error reporting and set it to ignore them.
Code:
error_reporting(E_ALL & !E_NOTICE);
If you are using methods from with in your Model in more ethan the one controller, you should autoload the model.
Check the /application/config/autoload.php file and add it in there.
