The captcha image is generated by the WA_ValidationToolkit/WAVT_CaptchaSecurityImages.php file. What happens if you preview that page in the browser?
Your friends over here at WebAssist! These Dreamweaver extensions will assist you in building unlimited, custom websites.
These out-of-the-box solutions provide you proven, tested applications that can be up and running now. Build a store, a gallery, or a web-based email solution.