Can't extend CI_Controller

[eluser]Lukas1[/eluser]
Hello,

1)I haven't changed the index.php file, but since I didn't change anything at all with the folder structure, I don't think this is the issue. If I indeed should have changed something in index.php, this should have been documented and I haven't found anything like this mentioned in documentation. If such thing would affect extending core classes, this should have been documented in the extending core libraries section(now it is not)
2)Yes, I've done that, but I don't see, how that is related, that's only URL and URL is not the deciding factor in finding path to core classes
3) I don't use .htaccess file for now, since I am only starting with my project, playing with CI etc...

I have pretty default setup, I mean, I really haven't done anything 'unusual' (if such term can be applied for trying out a php framework), I pretty much followed basic documentation, and it did work for me on my computer, so I really am not sure, what could possibly prevent loading my extended controller. I don't know, how is my extended controller being included(or how it should be included), if CI uses some kind of advanced php functionality, or if it is really only require/include functions...