Adding script? / php?

I was hoping to use this plugin to insert the Disqus universal code:

<div id="disqus_thread"></div>
<script type="text/javascript">
/* * * CONFIGURATION VARIABLES: EDIT BEFORE PASTING INTO YOUR WEBPAGE * * */
var disqus_shortname = 'severaldirections'; // required: replace example with your forum shortname

/* * * DON'T EDIT BELOW THIS LINE * * */
(function() {
var dsq = document.createElement('script'); dsq.type = 'text/javascript'; dsq.async = true;
dsq.src = '//' + disqus_shortname + '.disqus.com/embed.js';
(document.getElementsByTagName('head')[0] || document.getElementsByTagName('body')[0]).appendChild(dsq);
})();
</script>
<noscript>Please enable JavaScript to view the <a href="http://disqus.com/?ref_noscript">comments powered by Disqus.</a></noscript>
<a href="http://disqus.com" class="dsq-brlink">comments powered by <span class="logo-disqus">Disqus</span></a>

Putting this code between [insert_php] [/insert_php] doesn’t work. The code appears on the page. Is there something i can add, or I’m doing it wrong, or scripts can’t be added?

Thanks for any pointers.

http://ww.wp.xz.cn/plugins/insert-php/