PHP header: url_helper has failed me.

[eluser]xwero[/eluser]
The problem will be probably an extra space or line somewhere in your files. One way to prevent this is not using the end php bracket. If you were debugging and you output something to the page it's possible this is the problem.

For your third question. Isn't a cms an example of a user created content site Most people who ask questions are starting with CI or even with php and it's understandable people are not going to start with a complex website.