JFBConnet generate PHP Fatal Error in Joomla! 2.5.25

Dear Support,

When login using JFBConnect; meesage below was generated in Joomla Error Log;

line 164 refer here prntscr.com/4s0gz5
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[01-Oct-2014 17:46:45 Asia/Kuala_Lumpur] PHP Fatal error: Call to undefined method JDocumentOpensearch::addCustomTag() in /home/essenshe/public_html/plugins/system/jfbcsystem/jfbcsystem.php on line 164
[01-Oct-2014 17:46:59 Asia/Kuala_Lumpur] PHP Fatal error: Call to undefined method JDocumentOpensearch::addCustomTag() in /home/essenshe/public_html/plugins/system/jfbcsystem/jfbcsystem.php on line 164
[01-Oct-2014 17:47:04 Asia/Kuala_Lumpur] PHP Fatal error: Call to undefined method JDocumentOpensearch::addCustomTag() in /home/essenshe/public_html/plugins/system/jfbcsystem/jfbcsystem.php on line 164
[01-Oct-2014 17:47:09 Asia/Kuala_Lumpur] PHP Fatal error: Call to undefined method JDocumentFeed::addCustomTag() in /home/essenshe/public_html/plugins/system/jfbcsystem/jfbcsystem.php on line 164
[01-Oct-2014 17:47:28 Asia/Kuala_Lumpur] PHP Fatal error: Call to undefined method JDocumentFeed::addCustomTag() in /home/essenshe/public_html/plugins/system/jfbcsystem/jfbcsystem.php on line 164
[01-Oct-2014 17:47:33 Asia/Kuala_Lumpur] PHP Fatal error: Call to undefined method JDocumentFeed::addCustomTag() in /home/essenshe/public_html/plugins/system/jfbcsystem/jfbcsystem.php on line 164
[01-Oct-2014 17:47:38 Asia/Kuala_Lumpur] PHP Fatal error: Call to undefined method JDocumentFeed::addCustomTag() in /home/essenshe/public_html/plugins/system/jfbcsystem/jfbcsystem.php on line 164
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Need help.

problem solved after upgrading to v 6.2.1