You can fix the tab problem by setting the tabindex attribute for the fields. Just leave the top form tabindex values as 1,2,3,4 and update the bottom fields to use 11,12,13,14,15
I've gone ahead and made that update for you. The validation was failing because of a typo in the update I did for you on the wavt_captchasecurityquestion.php page. I've fixed that as well.