directory not found

I've just uploaded the ckeditor and ckfinder (licenced version). On my localhost the (demo) version works.
If I check the samples online, I get the error message: Map niet gevonden, vernieuw de mappenlijst of kies een andere map, or in english: Directory not found, refresh the directorylist or choose another directory.

What do I have to change in the config.php. I'm not a php expert ...