Google has recently updated the code snippet used to track conversions for AdWords. As of this writing the code in it’s native format will kick back a few errors when attempting to W3C validate. Here is how to fix those errors without breaking the code.
Here is the code in it’s original format.
<!– Google Code for [...]

You might have noticed that the new version of Google’s Analytics tracking code (ga.js) doesn’t validate using the W3C Validation tool. For those of us who like to write valid code there is an answer.
Look for this line in your ga.js code:
&lt;code&gt;document.write(unescape(”%3Cscript src=’” + gaJsHost + “google-analytics.com/ga.js’ type=’text/javascript’%3E%3C/script%3E”));&lt;/code&gt;

Replace it with this line:
&lt;code&gt;document.write(unescape(”%3Cscript src=’” + gaJsHost [...]