js scrolling divs positioning issue?

Hi

I hope this is the right forum to post in.

My front page has a series of scrolling photos with a semi transparent div on each with a link. The trouble is that whilst it works great in chrome, IE8 and firefox, the scrolling doesn't work properly in IE7. Can anyone help?
The front page is here http://www.cyclingnorth.com/

Many thanks
Tom.

Have a try adding:

#mainContent{position:relative}