External JS, JQuery

Hi!

I’ve got a problem with wp_enqueue_script (or just include JS script on my site).
Call of method with wp_enqueue_script:

<?php wp_enqueue_script('jquery')
    $path = get_bloginfo("template_url")."/banner/simpe.js";
    wp_enqueue_script("dupa", $path);
    wp_head();
?>

causes inclusion of text:

<script type='text/javascript' src='http://localhost/WPL/wp-includes/js/jquery/jquery.js?ver=1.4.2'></script>
<script type='text/javascript' src='http://localhost/WPL/wp-content/themes/main/banner/simple.js?ver=3.0'></script>

but the error console in Firefox tells me that my function is non definied. I also tried to include script in the same file where is the call of its method – then everything is ok.

Call of my method in file:

<script type="text/javascript">
   var $j = jQuery.noConflict();
   $j(document).ready(function() {
     simple();
   });
</script>

and external file:

function simple() {
   alert("i'm here");
}

What am I doing wrong? Please help me, codex haven’t helped and google too :-).
Thanks in advance.