CkFinder with Java with session issue?

I'm current working with CkFinder on JSF 2.0 (don't mention about this because i bet that the issue did not came from JSF), running on GlassFish Server 3.1.

I want to use CkFinder to provide user's private folder (each user have their own folder - let assume that the folder existed when they upload file).

First, I read this Document: http://docs.cksource.com/CKFinder_2.x/Developers_Guide/Java/Configuration/Extending

As the document said, i wrote a PathBuilder for that...

    @Override
    public String getBaseUrl(HttpServletRequest request) {
        String userFolder = request.getSession(true).getAttribute("userFolder").toString();
        return "/personalUpload/" + userFolder + "/";
}

But each time i press the "Upload" Button (the button to upload image to server after selecting multi file to upload to server), it create a new Session, and as a result, the session changed, and userFolder turned into null. (i dont' know why it created a new session ?)

How can i solve this problem?

Thank in advance

Snap shot:





Server Log (I created a Filter to write out all Session's ID request to my server)

Before pressing upload button:

INFO: Session ID = "e54c5282b348300eaa98ef3014cf"   Reqest : /Demo.Upload/ckfinder/core/connector/java/connector.java
WARNING: PWC4011: Unable to set request character encoding to UTF-8 from context /Demo.Upload, because request parameters have already been read, or ServletRequest.getReader() has already been called

INFO: Session ID = "e6b68691c72b4527717f4d5daad9"   Reqest : /Demo.Upload/ckfinder/core/connector/java/connector.java
WARNING: PWC4011: Unable to set request character encoding to UTF-8 from context /Demo.Upload, because request parameters have already been read, or ServletRequest.getReader() has already been called
SEVERE: javax.servlet.ServletException: java.lang.NullPointerException