with ckfinder, the page is blocked

Hello,
I'm sendig you this message to get help.
I'm a little loose trying to set up ckeditor on ckfinder.
The fact is that when I used only ckeditor in my form everything works.
Afet having set up ckfinder, when I click on "browse" and I choose a picture
to get it in a text editor, and when I validate, the page is getting blocked. there is a kind of transparent layer on top of the page (like in Windows when a program is blocked). I do not know what to do.
Can you help me?
In advance thank you.

A user whos is a little lost in these wonderful programs that are CKEditor and CKFinder.

It's looks like this
but first of all when I click on "browse" or "explore the server", and I select a folder it's says" you do not have the right to access on this folder" or something lke that. when I click a second time on the same folder its works... Anyone is able to help me?

thanks a lot