site doesn't load with include path

[eluser]Aken[/eluser]
An application package is a folder with various CI-like subfolders (models, helpers, libraries, etc). Adding the application path tells CI to look for files in these folders as well as in your /application/... and /system/... folders. Read the user guide page for more information, that's why I linked it.

I'm under the assumption that you have multiple CI applications on the same server, all with access to the common /includes/ folder. If you are trying to use one shared folder between multiple servers, that is inadvisable for a bunch of reasons.