A: 

Edit Answer left for context. See @Triptych's (accepted) answer for the correct resolution.

My suggestion is to move the inclusion of the javascript to the end of your mark up. I think what is happening is that the code is executing before the DOM is completely loaded and thus the document.body is null when you try to reference it in determining the maxHeight style property. Moving the inclusion of the javascript to the end of your markup should be enough to guarantee that the body of the document is loaded at least and avoid this particular error.

 ... rest of html....

    <script type='text/javascript'
            src='http://www.457cc.co.nz/facelift/flir.js'&gt;
    </script>
 </body>
 </html>
tvanfosson
Almost. Including the file doesn't actually access the DOM. He has a script block in the page that actually runs the init script that causes the answer. See my answer.
Triptych
Thanks for your answer I don't think I would have figured out that it has to do with the page loading any time soon..
Jannis
@Triptych -- I was just going by the error. Hadn't actually looked at his page. Good catch. I'll leave my answer here for context since you reference it. +1 to you.
tvanfosson
+6  A: 
Triptych
Thank you. Works like a charm!I cannot believe I wasted 6 hours on this yesterday with a solution being as simple as including a document ready statement.
Jannis
No problem. Every Javascript ninja has once battled with the ol' "accessing the DOM before page load" error. Pretty common.
Triptych
A: 

Install .net Framework v2 and solve the problem..

tnx tnx tnx...