Turning off Category-Tabs Menu also turns off logo in IE7

[Rubylily]

Hello

I've only just started using Zen Cart, so I'm not very familiar with all the ins and outs of it yet. I can't see this posted elsewhere, so apologies if it has already been discussed. When I turn off the Category-Tabs menu in the Admin my logo and the bottom half of my header completely disappear when viewed in IE7. When viewed in FF2 there is no problem. So I'm a bit baffled. Is this a known bug? Or is it something silly I've done myself? The url is www.myarosa.co.uk/index.php (not much to look at yet, I've only just started work).

Thanks,

Lois

[Rubylily]

Can't find an edit button, forgot to add that I'm using v1.3.7.