why cant add this html in my portal?

Why when add this html in my portal it doesnt show anything??

Code:

<script type="text/javascript"><!--
google_ad_client = "pub-1554613414416359";
//200x200, δημιουργήθηκε 15/12/2007
google_ad_slot = "3357687298";
google_ad_width = 200;
google_ad_height = 200;
google_cpa_choice = ""; // on file
//--></script>
<script type="text/javascript"
src="http://pagead2.googlesyndication.com/pagead/show_ads.js">
</script>
<script type="text/javascript"><!--
google_ad_client = "pub-1554613414416359";
//728x90, δημιουργήθηκε 15/12/2007
google_ad_slot = "8833759196";
google_ad_width = 728;
google_ad_height = 90;
//--></script>
<script type="text/javascript"
src="http://pagead2.googlesyndication.com/pagead/show_ads.js">
</script>

these dont work on portals

and where it works????

u can go to General homepage configuration scroll down homepage message type this code <br> and put ur script after this and press save it will apear on the forum