Set up ckFinder config.php

try the obvious?

change baseurl to

$baseUrl = 'http://www.yourdomain.com/cfk/ckfinder/userfiles/';

^^ check the path is correct and that you are using a folder called userfiles to store the files ofcourse

the baseDir uses resolveUrl, i dont have the code open or at hand but im guessing that function is probably a wrapper for something like getcwd() which basically will take the current directory of the executing php file and append userfiles to it. If you want to make sure this is working properly just set the basedir absolutely too, so for example:

$baseDir='/var/www/mysite/ckf/ckfinder/userfiles/';

if that doesnt work, id leave it in anyway, it wont hurt (as long as you set them correctly).

If that fails check the popup. or whatever page the popup is created from, if you have put the link in yourself, or copied and pasted a link then make sure the link href/src is correct and if its a relative link (i.e. "/ckfinder.html") be aware that the forward slash at the start will cause it to drop back to the main domain base directory so you will either need to change the href/src to be one of these:

http://www.mydomain.com/ckf/ckfinder/ckfinder.html (i like absolute links, i recommend them)
/ckf/ckfinder/ckfinder.html (drops back to root and traverses back up the dir structure to the file)
ckfinder.html (notice: no forward slash at start, basically means, look in the same directory as the file the link is placed on)

however if any of the above is new too you, then you really should get your head into a cookbook and gain some basic knowledge before attempting using this. else you'll just be opening a big door for malicious users into your server.