Undefined index error in Loader.php
I'm trying to install fuel on an existing CodeIgniter site. I put all my models / controllers / views / libraries in the appropriate fuel/application folders and merged my config files with fuel's. I keep getting "Undefined index" error in Loader.php line 206:
$_alias = $this->_ci_classes[$class];
When I take out items in my autoload.php it errors out on my different libraries (I believe it choked on SimpleLoginSecure.php), right now it's saying Undefined index: MY_Session. Can you help?