Now if you just pasted that ad unit code directly into your Blogger header you’d get an error or it just wouldn’t work. Most people would think Blogger was broken or wonder if it’s something they did when in fact it’s neither. The new Blogger uses xml which is much more strict and requires certain reserved characters like > < or & to be converted into xhtml entities. Here’s what your ad code needs to look like in order to work properly:
<script type="text/javascript"><!--
google_ad_client = "pub-6044026340890176";
/* 468x60, created 3/17/08 */
google_ad_slot = "3105157606";
google_ad_width = 468;
google_ad_height = 60;
//-->
</script>
<script type="text/javascript"
src="http://pagead2.googlesyndication.com/pagead/show_ads.js">
</script>
This only took me a few seconds to convert since I used the free and easy Blogger Ad Code Converter. There are actually posts out there that explain how to do this manually but who wants to take the time searching and replacing each character when you can convert unlimited sized ad code blocks with only one click?