After installing CKFinder according to the instructions in the CKEditor module README.txt I was getting the following error displayed in the CKFinder dialog:
It was not possible to load the XML response from the web server. The server returned an empty response.
In my case I have ckeditor and ckfinder installed in sites/all/libraries/ and the ckeditor module installed in sites/all/modules/ckeditor . I'd imagine this would be a common configuration.
The path in line 191 of the readme isn't correct for the above case. It needs to instead be:
Because the error message is obtuse, I'd imagine many people have had the same frustrations. I hope this helps them. I suggest updating the readme.