Going directly to your webassist/captcha/wavt_captchasecurityimages.php page, I get the error message: "<b>Fatal error</b>: Call to undefined function imagettfbbox()". This usually indicates that either (or both) the GD Library and Freetype support has not been enabled in your remote sever configuration.
Looking at the results of your phpinfo.php, you have the GD Library enabled, but there is no support for FreeType. You will need to contact your hosting provider and ask them to enable support for Freetype on your remote sever configuration (php.ini).
i.e: