Adsense ads not visible mostly times?

[ZEEn]

Hello
i am using tribune theme for my site http://www.tajveez.com
I already use this theme on my other site every thing is fine but on thus site. about 50% times ads not visible. specially on home page ads box remains always empty. i placed 2 ads on home page both are not visible, an don inner pages only start and end of articles ads visible some times mostly time show blank spaces.
Where is the issue? its theme problem or some thing else?
Thanks
and one last thing on my home page never ad displayed, i even not click on adsense that show blank space when no ad available.

[Ferdinand]

Well that simply means there is no ads available for display on that page, remember the adsense setup that requires you to choose alternative content to display on an ads space when there is no ads available that means there could be times when ads will not be available.