Erreur Strict Standards: strtotime():...

Bonjour,
voilà après plusieurs recherches je n'arrive pas à résoudre mon problème alors j'espère que vous pourrez m'aider.

Mon problème et le suivant:

Strict Standards: strtotime(): 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 'Europe/Berlin' for 'CEST/2.0/DST' instead in /homepages/ **/********* /htdocs/dev_beta_v2/lib/Cake/Cache/CacheEngine.php on line 59
Strict Standards: strtotime(): 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 'Europe/Berlin' for 'CEST/2.0/DST' instead in /homepages/ **/********* /htdocs/dev_beta_v2/lib/Cake/Cache/CacheEngine.php on line 59

Je pense que c'est en rapport avec le fuseau horraire mais si c'est bien ça, comment je le modifie?

Merci d'avance.