This solution is a quick work around to the problem.

edit the file */mod/messageboard/views/default/widgets/messageboard/veiw.php

**(Copy and paste the text in the box and paste it over the contents of the file.)

     /**
     * Elgg messageboard plugin view page
     *
     * @todo let users choose how many messages they want displayed
     *
     * @package ElggMessageBoard
     * @license http://www.gnu.org/licenses/old-licenses/gpl-2.0.html GNU Public License version 2
     * @author Curverider Ltd <info@elgg.com>
     * @copyright Curverider Ltd 2008-2009
     * @link http://elgg.com/
     */
     
     // a couple of required variables
     
     //get the full page owner entity
     $entity = get_entity(page_owner());
    
     //the number of message to display
     $num_display = $vars['entity']->num_display;
    
     //if no num set, set to one
     if(!$num_display)
        $num_display = 5;
     
//Just the loggedin user can send messages
if(isloggedin()){
?>
    <script type="text/JavaScript">
    $(document).ready(function(){
        
        $("#postit").click(function(){
           
            //display the ajax loading gif at the start of the function call
            //$('#loader').html('<img src="<?php echo $vars['url']; ?>_graphics/ajax_loader.gif" />');
            $('#loader').html('<?php echo elgg_view('ajax/loader',array('slashes' => true)); ?>');
           
            //load the results back into the message board contents and remove the loading gif
            //remember that the actual div being populated is determined on views/default/messageboard/messageboard.php    
            $("#messageboard_wrapper").load("<?php echo $vars['url']; ?>mod/messageboard/ajax_endpoint/load.php", {messageboard_content:$("[name=message_content]").val(), pageOwner:$("[name=pageOwner]").val(), numToDisplay:<?php echo $num_display; ?>}, function(){
                        $('#loader').empty(); // remove the loading gif
                        $('[name=message_content]').val(''); // clear the input textarea
                    }); //end
                    
        }); // end of the main click function
           
    }); //end of the document .ready function  
    </script>
   
    <div id="mb_input_wrapper"><!-- start of mb_input_wrapper div -->
   
        <!-- menu options -->
        <div id="messageboard_widget_menu">
            <a href="<?php echo $vars['url']; ?>pg/messageboard/<?php echo get_entity(page_owner())->username; ?>">Write Message</a>
        </div>
       
        <!-- loading graphic -->
        <div id="loader" class="loading">  </div>
   
    </div><!-- end of mb_input_wrapper div -->

<?php
} //    if(isloggedin())
   
        //this for the first time the page loads, grab the latest 5 messages.
        $contents = $entity->getAnnotations('messageboard', $num_display, 0, 'desc');
       
        //as long as there is some content to display, display it
        if (!empty($contents)) {
           
            echo elgg_view('messageboard/messageboard',array('annotation' => $contents));
       
        } else {
           
            //put the required div on the page for the first message
            echo "<div id=\"messageboard_wrapper\"></div>";
   
        }
   
?>

Not the best solution but works around the problem.

** Also address the "Message Board error when not logged in" bug reported by rwallace

thanks to the patch posted by pedroprez.