Insert record page - works in Safari, but not IE / Firefox

Question

I've been working on a form where users can post an enquiry to a database.
Thought it was all starting to come together, but I noticed at another client's today that it didn't work in IE.
In Safari you fill in the form, hit the Post Enquiry button and you go to an Enquiry Added page.
In IE / FF it looks as though the page just refreshes, and nothing happens...
You can see what I mean by logging in here with:
testusername
testpassword
and click on Post Enquiry
http://www.goodsafariguide.com/consumer_login/
Any ideas why that would be or how to fix it?
Thanks.

Answer 1

Well, after about five hours retracing my steps, I finally figured out the offending code - it was the submit button.
On this page:
http://www.goodsafariguide.com/consumer_add_query/index.php
It works fine with:
<input type="submit" name="KT_Insert1" id="KT_Insert1" value="Post your query" />
But on this page:
http://www.goodsafariguide.com/consumer_add_query/indexb.php
It only works in Safari with:
<input name="KT_Insert1" type="image" id="KT_Insert1" onmouseover="MM_swapImage('KT_Insert1','','../images/buttons/post_enquiry2.jpg',1)" onmouseout="MM_swapImgRestore()" value="Post your query" src="../images/buttons/post_enquiry1.jpg" border="0" />
As its now nearly 2:30am, I'm not going to try to figure why that should be right now.
Its nothing if not frustrating sometimes, this web design lark!