If your website or pages display this error don’t panic! it should be a quick and easy fix!
Simply add the following line to your php.ini file, usually located in /etc/php.ini
date.timezone = "England/London"
(You can of course use your country / city! this is just an example!)
Alternatively, if your site it using cgi / fastcgi and you are on a multi domain or shared host you may have to add the line to the php.ini located in your actual webspace, usually again in the /etc directory.