Hello,
This error may be related to php version or missing php modules:
http://www.sitepoint.com/forums/showthread.php?431662-Fatal-error-Call-to-undefined-function-imagettftext%28%29
http://stackoverflow.com/questions/7290958/php-fatal-error-call-to-undefined-function-imagettftext
So please ask your host to check it.
Thank you.
Regards,
Eva Kemp.