I was working on my project and implementing KCEditor and CKFinder (the free one) with image upload, but when i tried to upload image i found error like "you don't have permissions to upload files".
So, i though maybe issue for folder permission because i used ubuntu OS. i gave whole ckfinder folder give full permission 777 and also give ckeditor folder too. but same error. At last i found how to solve it. So if you have also fetch this error then you have to open config.php file in conf folder of ckfinder and disabled equal to give false.
'disabled' => true,
'disabled' => false,