flexslider bug

[ejlocop]

Hi, im having trouble using flexslider, (http://flexslider.woothemes.com/basic-slider-with-caption.html)
the images on slider didnt show on either $(window).load(), $(window).ready(), $(document).ready();
and how can i set the fixed height of slider images?
(see screenshot)

and here is my code
$(window).ready(function() {
$('.flexslider').flexslider({
animation: "slide"
});
});
// or
$(window).load(function() {
$('.flexslider').flexslider({
animation: "slide"
});
});
// or
$(document).ready(function() {
$('.flexslider').flexslider({
animation: "slide"
});
});

either ways didnt show proper result. please help.