you are using some plugin in your broswer that is blocking adds for you. i think they will be visible to rest
Have you verified your adsense account. Asense sends a verification PIN after you earn your first $10, if not that apply for PIN and verify it.
for the first time it takes some time for ads to display..... check in some other browser as well. But really its nothing you should be worried about. Just start promoting your site and enjoy the $$$$$
Have you entered adsense code properly? If it shows blank space on adsense block then wait for few minitu. It takes a time to appear on your site.