Accordion with dynamic content and collapsible:true issues

Accordion with dynamic content and collapsible:true issues

As a test I have the following js:
<script type="text/javascript">
$(document).ready(function(){
    $('#accordion').accordion({change: function(event, ui) {
            $('#'+ui.newHeader[0].id+'-content').load(ui.newHeader[0].id
+'.html');
        }});
});
</script>
and the following HTML:
<div id="accordion">
    <h3 id="article1">head1</h3>
    <div id="article1-content"><img src="ajax-loader.gif" /></div>
    <h3 id="article2">head2</span></h3>
    <div id="article2-content"><img src="ajax-loader.gif" /></div>
    <h3 id="article3">head3</h3>
    <div id="article3-content"><img src="ajax-loader.gif" /></div>
</div>
and this all works as expected.
But when I add "collapsible:true, active:false" to the options it will
work only as long as I don't collapse the accordion entirely.
I will get the following error: message: Statement on line 4: Cannot
convert undefined or null to Object
I only have a basic understanding of javascript/jquery.
What am I missing?
Thanks.
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