You might try replacing:
imagecreatetruecolor
with:
imagecreate
in the file: WAVT_CaptchaSecurityImages.php
I think it only appears once on line 89
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.