ERROR

Sorry bad things have happened :(.
                STACK TRACE = #0 /home/pysclub/www.pysc.org.uk/article.php(15): User_Session::error(Array)
#1 {main}        REQUEST= Array
(
    [a] => 506
)
        REQUEST= Exception Object
(
    [message:protected] => Error
    [string:Exception:private] => 
    [code:protected] => 0
    [file:protected] => /home/pysclub/www.pysc.org.uk/class/User_Session_class.php
    [line:protected] => 102
    [trace:Exception:private] => Array
        (
            [0] => Array
                (
                    [file] => /home/pysclub/www.pysc.org.uk/article.php
                    [line] => 15
                    [function] => error
                    [class] => User_Session
                    [type] => ::
                    [args] => Array
                        (
                            [0] => Array
                                (
                                    [Id] => The Id field is required
                                )

                        )

                )

        )

    [previous:Exception:private] => 
)