Masthead looks fine in IE7, FF and Opera, but not in IE6 or Safari - help needed

Hi there,

I have designed my masthead and everything looks fine in IE7, FF, Opera. But in IE6 things are way out or just not showing. In Safari my gradient background image is slightly too low.

The page validates for both HTML and CSS but I just dont know what is causing things to appear incorrectly in IE6 and Safari.

If anyone can shed any light I'd really appreciate it!

http://www.tomkilbourn.com/tomkilbourn/masthead2.html

eliminate the body { margin:5 px;} to start with

ok i will remove it, but can you give me more info as to why it needs to be removed? It will help me for future reference. Thanks :)