wordpress flexslider is not a function

I’m developing custom theme for wordpress and using META SLIDER plugin for that, but in rendering page. in firebug result that says:

$(...).flexslider is not a function

line 242 :

useCSS:false

full attached java script with plugin:

<script type="text/javascript">
    var metaslider_99 = function($) {
        $('#metaslider_99').flexslider({ 
            slideshowSpeed:3000,
            animation:"fade",
            controlNav:true,
            directionNav:true,
            pauseOnHover:true,
            direction:"horizontal",
            reverse:false,
            animationSpeed:600,
            prevText:"<",
            nextText:">",
            easing:"linear",
            slideshow:true,
            useCSS:false
        });
    };
    var timer_metaslider_99 = function() {
        var slider = !window.jQuery ? window.setTimeout(timer_metaslider_99, 100) : !jQuery.isReady ? window.setTimeout(timer_metaslider_99, 100) : metaslider_99(window.jQuery);
    };
    timer_metaslider_99();
</script>

Is this an issue of the order of the stacking of the javascript files?

LINK:
Please see this link