You're only allowed a max of 3 ad units on a page & any more than that will not show. You have 4 which is a policy violation & that can get the site or whole account disabled even though the 4th one isn't showing. It's also a violation to alter the size of the ads & Adsense doesn't have a 480x80 ad unit. If you changed it from 480x60 that is also another violation that can get your account disabled.