Sidebar Disappears on Only 1 Page – a Category page?

I’ve got a problem when viewing my blog and it’s only when viewing from IE7 as far as I can find.

When I select just one category and move to the page the right sidebar vanishes.

It only happens on this one page which is my first category in my list of categories.

I think it’s strange that it only happens on that one category but have no idea what it would take to see whats wrong?

Help is appreciated.