if I try to browse directly to the file that generates the captcha image:
wavt_captchasecurityimages.php
i see the following error:
Fatal error: Call to undefined function: imagecreatetruecolor() in c:\program files\server\apache\www\weddingvideonz\webassist\captcha\wavt_captchasecurityimages.php on line 89
this error means that the GD library needed for generating the image is not enabled on your server, you will need to contact your host to have the GD Library enabled in the php installation.