Thank you for coming back to me, I will check and look at the areas you've mentioned and post some results.
--------------- Added [DATE]1255015932[/DATE] at [TIME]1255015932[/TIME] ---------------
Ok, I opened the page source and straight away saw that Firefox was marking the "/" at the end of my command in red.
Red isn't good, so I looked at how vBulletin scripts are details and used the same format, i.e.
Code:
<script type="text/javascript" src="wowarmory_tooltip/js/wat.js.php"></script>
At the moment, it all seems to work!