BUG: When cookie has array, click upload failed

:
0. CKFinder version is 2.1
1. Write an array to cookie
2. Open CKFinder, and click upload button
3. CKFinder popup a dialog says:

It was not possible to properly load the XML response from the web server.
XML Parsing Error: junk after document element Location: http://localhost:8080/js/ckfinder/ckfin ... angCode=en Line Number 2, Column 1:Warning: htmlspecialchars() expects parameter 1 to be string, array given in E:\xampp\htdocs\app\webroot\js\ckfinder\core\connector\php\php5\Utils\XmlNode.php on line 174
^
Raw response from the server:

<?xml version="1.0" encoding="utf-8"?><br />
<b>Warning</b>: htmlspecialchars() expects parameter 1 to be string, array given in <b>E:\xampp\htdocs\app\webroot\js\ckfinder\core\connector\php\php5\Utils\XmlNode.php</b> on line <b>174</b><br />
<Connector resourceType="Images"><Error number="0" /><CurrentFolder path="/" url="/upload/images/" acl="255" /><Cookies><Cookie name="CAKEPHP" value="4c583a36500d6b970f0e8d9d087b0de6" /><Cookie name="sdcms" value="" /></Cookies></Connector>