Enabled Captcha and now cannot login to Manager

I am really stuck now after turning this on. Apparently it has something to do with GD and Freetype however I have no idea what to do to resolve this.

I have an Apache server but do I need to install some new programs on it? Or change something in my PHP.ini file?

Thanks!

Not knowing how to do this myself, I have asked our Server host techies to enable the GD Library (we use PHP Version 4.4.4) and he did. Unfortunately, now my website does not work at all and all I get is a message that says:

Fatal error: Call to undefined function: preg_replace() in /home/----/www/----.com/manager/includes/protect.inc.php on line 34

Hopefully this error is trivial and can be solved fairly quickly.

Any suggestions? Thanks!

The preg functions are in the PCRE library i.e PCRE (Perl Compatible Regular Expressions) Support, this has to be enabled in your php setup, check for the entry pcre in phpinfo() or in php -i from the command line.