I got this error when I requested to update the PHP version from 5.2.17 to PHP 5.3.21 on the server.
This issue has been bugging me for SOME time as im trying to inject a "createbucket.php" script into composer and i keep being told my time-zone is incorrect.
In the end the only thing that fixed the issue was to:
$ sudo nano /etc/php.ini
Search for timezone
[Date]
; Defines the default timezone used by the date functions
; http://www.php.net/manual/en/datetime.configuration.php#ini.date.timezone
date.timezone = UTC
Ensure you remove the ;
Then finally
$ sudo service httpd restart
And you'll be good to go :)