mcjim

If that’s the Theme you’re using, then, yes, the styles.css file is the one you want to change. Just to make sure, you can always change the background colour to something horribly noticeable and then change it back again.
Haven’t got a copy of IE with me at the moment. The div is centred in FF and Safari. Use the Firebug extension in FF to try to locate the CSS errors. The page doesn’t validate (http://validator.w3.org/check?verbose=1&uri=http%3A%2F%2Fmysattrack.net%2F), so perhaps start there. Good luck.

Is that IE5.x? Should be fine in 6 and above, as long as it’s in compliance mode.
It’s because 5.0 can’t cope with the margins being auto. See http://css-discuss.incutio.com/?page=CenteringBlockElement
The footer is sticking out because it’s the child of the “content” div.
Hope this helps.