ERROR

Sorry bad things have happened :(.
                STACK TRACE = #0 /home/pysclub/www.pysc.org.uk/class/Article_class.php(177): User_Session::unauthorized('')
#1 /home/pysclub/www.pysc.org.uk/class/Article_class.php(184): Article->authorize()
#2 /home/pysclub/www.pysc.org.uk/article.php(21): Article->get_title()
#3 {main}        REQUEST= Array
(
    [id] => 749
)
        REQUEST= Exception Object
(
    [message:protected] => Unauthorized 
    [string:Exception:private] => 
    [code:protected] => 0
    [file:protected] => /home/pysclub/www.pysc.org.uk/class/User_Session_class.php
    [line:protected] => 91
    [trace:Exception:private] => Array
        (
            [0] => Array
                (
                    [file] => /home/pysclub/www.pysc.org.uk/class/Article_class.php
                    [line] => 177
                    [function] => unauthorized
                    [class] => User_Session
                    [type] => ::
                    [args] => Array
                        (
                            [0] => 
                        )

                )

            [1] => Array
                (
                    [file] => /home/pysclub/www.pysc.org.uk/class/Article_class.php
                    [line] => 184
                    [function] => authorize
                    [class] => Article
                    [type] => ->
                    [args] => Array
                        (
                        )

                )

            [2] => Array
                (
                    [file] => /home/pysclub/www.pysc.org.uk/article.php
                    [line] => 21
                    [function] => get_title
                    [class] => Article
                    [type] => ->
                    [args] => Array
                        (
                        )

                )

        )

    [previous:Exception:private] => 
)