I can see the ad is floating over your header/logo. If you are using Thesis OpenHook to add the advertisement to your header, style it with html, something like this:

Give your image a div id of “header_advert”

Then, add some css like this – you’ll have to adjust the top padding and padding-left to get it to sit in the right place in your header area:

.custom #header_advert {float: right; position: absolute; width: 468px; height: 60px; top: 50px; padding-left: 460px;}