Fatal error in widget

May I ask what is your PHP version?
If it is older than 5.3, that might be the reason for this error message

Hi, I use WP 3.5.1.

That’s the WordPress version, but what about your PHP version? It appears that your host is using an older version of PHP. Contact your host provider and ask them for the PHP version or otherwise type phpversion() and see what you get.

Sorry, misread. PHP Version 5.2.17

Looks like that method is only available in php version 5.3+. I will modify it for compatibility with older versions of php also. Thanks.

class MyDateTime extends DateTime {
public function getTimestamp() {
return method_exists(‘DateTime’, ‘getTimestamp’) ?
parent::getTimestamp() : $this->format(‘U’);
}
}