problema con la funcion date() en el servidor y la aplicacion dokeos

[juanjoselive]

hola compañeros buenas tardes.
quisera saber si alguien sabe como arreglar el error siguiente

arning: date() [function.date]: 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/Chicago' for '-6.0/no DST' instead in C:\xampp\htdocs\dokeos\main\inc\lib\main_api.lib.p hp on line 1772

Warning: date() [function.date]: 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/Chicago' for '-6.0/no DST' instead in C:\xampp\htdocs\dokeos\main\inc\lib\main_api.lib.p hp on line 1772

Warning: date() [function.date]: 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/Chicago' for '-6.0/no DST' instead in C:\xampp\htdocs\dokeos\main\inc\lib\online.inc.php on line 53

sera que tengo que cambiar la hora del servidor o de la aplicacion gracias por sus comentarios y sugerencias
estoy trabajando con xampp y dokeos 1.8.6.1
gracias

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