[Plugin: Contact Form 7] use google analytics in form problem

Hi, I’m trying to use google analytics in the contact form, I read this http://contactform7.com/2009/11/24/tracking-form-submissions-with-google-analytics/ but does not work, I have an error javascript that says this:

Message: ‘pageTracker’ is undefined
Line: 49
Character: 47
Code: 0
URI: http://www.xxxxxxxxxxxxxxxxxxxx.com/wp-content/plugins/contact-form-7/scripts.js?ver=2.4.1

What is pageTracker?