AdSense on the Contentpage

Hi,
I’d like to put some AdSense-Banner between the text on my homepage. There is already a working Banner in the sidebar. But always, when i try to put some to the Content-Page, they do not show up.

Is there a setting, i have to change, to be able to do it? It is not a Plugin-Problem, because it also doesn’t work, if i just put the plain AdSense-Code directly to the text-page.

Any ideas?
Thank you very much!

Roman