Can’t write comments in IE

My comments form is having problems in Internet Explorer – the button refuses to work – but it works fine in Firefox.

I know this is probably a general coding issue rather than a WordPress-specific problem but if anyone could help I would be most grateful.

Here is a sample page which has the problem: http://www.jonpashley.co.uk/the-brothers-size/

I think I’ve narrowed down the cause, or at least a symptom of the problem, to one <\div> (in the source I have labelled this with a comment as ‘Problem div’). When I remove it, the form works in IE but it traps my footer within the page wrap.

Any suggestions?

Many thanks,

Jon