[Dismounted]

Originally Posted by Wayne Luke

In order to use GD Based Image verification in 3.7.0 and higher, you need to have Freetype2 support compiled into PHP.

Most likely the original PHP configure string contained --with-freetype but this usually only enables support for Freetype version 1, which does not support True Type fonts.

To enable Freetype 2 support (assuming that the server has the Freetype 2 libraries installed), this part of the configure string neeeds to be removed and replaced with (normally) --with-freetype-dir=/usr

To find out if a Linux server has Freetype 2 support, run locate freetype2 at the command line and look for some results, usually in /usr/include/freetype2.

The above only applies for using vBulletin's own CAPTCHA.

At your forum, you have chosen reCAPTCHA and the error tells you that you have not entered the key pair properly.