Hola, me baje el Piwigo y al ejecutarlo en local me sale este error:

Warning: strftime() [function.strftime]: It is not safe to rely on the system's timezone settings. You are *required* to use the date.timezone setting or the date_default_timezone_set() function. In case you used any of those methods and you are still getting this warning, you most likely misspelled the timezone identifier. We selected 'America/New_York' for '-5.0/no DST' instead in C:\xampp\htdocs\gantigua\include\smarty\libs\Smarty_Compiler.class.php on line 409

Me pueden colaborar con esto.
Muchas gracias y feliz día.