hello webmaster

Hello, I'm a new guy to php recently I've been getting this error in my site.. specially when I try to do a backup 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 'Europe/Berlin' for 'CEST/2.0/DST' instead (2) I really dn't know what to do this server is unmanaged. Please if someone could help me fix this error. I really need some guide bcuz I'm not good with php editing. Thank you Anthony