cookies dont work correct

[eluser]axisdude[/eluser]
Ive read it.
Im not an expert with CI...
I having troubles to understand what it is exactly what i need todo.
Perhaps its easyer that some1 tell me wich files are all needed for the cookies to work, then i can post them here.
then you can have a look on whats wrong.

Im using premade script fom xtrafile, since their support is not available im looking here for support.
so.. sorry for my noob questions.
thx in advantage.