No Ads visible, how to handle multisite?

Hi

I'm new at doubleclick. Just getting around with it.
I've installed the modul, put there the id, the ad slots.
At doubleclick I put the ad slots, olacements, creatives.

But it's still not working. What have I forgotten?
Testing page at drupal is still empty.
Ads at doubleclick still at "ready". Not delivering.
Any code? Or what else?

And how can I get there multisites? with similar ad slots?

Any ideas? Urgently looking for help!