Double opt in problem

I have followed the video tutorial several times and keep having problems. The verification email is sent but when the verification link is clicked, the page that loads is blank and the emailVerified row of the db does not update from 0 to 1. The URL for the verification link is in this format - http://www.letsparksfly.com/userconfirm.php?id=1&randomString=t6he9m&email=dgwebs@gmail.com. All of the variables are correct. In this instance, the userID is 1, the randomString is correct (based on the one showing in table), and the email is correct.

In the tutorial at 22:53 of the video tutorial a session value is being added to the userconfirm page and in the dialog box that appears, the session variable name defaults to emailVerified. I do not have a session variable of emailVerified available. I notice earlier in the video that session variable appears in the bindings panel but it is has never appeared in mine in any of the six times I've tried this. Could that be my problem?

Many thanks for your help!