Debbie...
A custom channel is what you should have not a URL in my opinion
except you probably made the same mistake I made... I put in TWT instead of 98457493 (fake numbers, but what is supposed to go in instead of the
name of the channel)
Code:
<script type="text/javascript"><!--
google_ad_client = "pub-459083475045748";
google_ad_width = 728;
google_ad_height = 90;
google_ad_format = "728x90_as";
google_ad_type = "text_image";
google_ad_channel ="09384233";
//--></script>
<script type="text/javascript"
src="http://pagead2.googlesyndication.com/pagead/show_ads.js">
</script>
The bolded numbers above are what you should have put in (the numbers have been changed to protect my account )
So if you go back to your Control panel here at TWT and put the google_ad_channel numbers in where it asks for your channel then you will start to see the page impressions
hope that clears it up for you
NeO