What template are you using? In my template, the description.phtml and tabs.phtml are separate files. Check your app/design/frontend/default/your_template/template/catalog/product/view folder to see if you have both of these. If you don’t then these children are hardcoded somewhere and we’ll have to find them. If you see both, then the above code will work if you haven’t modified your code. Check it and get back to me.