When I try to view the captcha image directly at: http://www.vehiclewrappricing.com/webassist/captcha/wavt_captchasecurityimages.php
I see the error: Call to undefined function imagettfbbox()
This means that you don't have the GD library enabled in your php.ini file. Enabling that library should allow CAPTCHA to display.
The Show-if messages appear correctly for me. It looks like you also have client validation, so you would have to pass all of the client validation fields before the server validation would take effect and show any messages. Client validation precludes the server validation and any server errors.