<H1> problems...not working in ie

[SIMONdesign.nl]

Can someone help me solve this? One of my websites doesn't display -tags in internet explorer (it does work in ff, safari)

http://www.bedrijfswageninbouw.nl/site/index.php

Did I forget a piece of code? 

tnx

[Jean le Chauve]

I can see with ie6, ie7, ff3 and opera.
Problems with the design in opera.
Tables, invalid code and invalid css.

[christiaans]

I do see a h1 tag in IE6.. it's just styled like normal text..only bold..

I do see a lot of validation errors, as mentioned by Jean le Chauve.

[Dr.CSS]

You will get all kinds of strange looks when you have an open div call in template...

<div id="mn"