This is a server configuration issue and should be set at the server level in the php.ini file. However you can override the issue by setting a locale in your config.php file.
See:
http://php.net/manual/en/function.da...mezone-set.php
You would use something like:
date_default_timezone_set ('America/Los_Angeles');
You can find all timezones here:
http://www.php.net/manual/en/timezones.php
Really should be set in the php.ini file in this section of code:
Turning display errors off would also eliminate the problem. They aren't errors, simply warnings. They are due to how PHP has changed over the years. Previous to vBulletin 4.2.2, they were suppressed because vBulletin didn't know how to deal with them.