tracking conversion rate from google adword -- 2

Hello everybody, I have a running Wordpress website, and I am advertising via Google Adwords. To be more efficient, I would like to track after the words that make conversion. Conversion is the people who leave their information for a call back in the “contact form 7” plug in. What I believe needs to be done is to create a Thank you page and redirecting to it from the contact 7 plug in. and then put the Google tracking code. When I create the new page it open it with 500 server error, but while I create a page in other theme it comes up smoothly. So the job is to track conversion from googl adwords.