I have upgraded my PHP from version 5.2.9 to 5.3.1 and have encountered the following with my codeigniter application:
Unable to locate the model you have specified: some_model
Codeigniter version 2.1, with HMVC extension Server: Centos 5
The model names are all in lower case and it is also loaded by calling their lower case letter. Everything used to work before the PHP upgrade.
Make the second parameter to TRUE: