#1232 How do I fix this?

[Evelyn McCorkell]

WHAT DOES THIS MEAN - HOW DO I FIX?

ERROR 2: 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 'Australia/Melbourne' for 'AEDT/11.0/DST' instead
0 Error occurred on in function date
1 called from line 356 of file session.php in function require_once
2 called from line 75 of file config.php in function require
3 called from line 29 of file index.php

ERROR 2: session_start() [function.session-start]: Cannot send session cookie - headers already sent by (output started at /home/allau/public_html/mccorkell.info/cms/phpgedview/includes/functions/functions.php:500)

ERROR 2: session_start() [function.session-start]: Cannot send session cache limiter - headers already sent (output started at /home/allau/public_html/mccorkell.info/cms/phpgedview/includes/functions/functions.php:500)
0 Error occurred on in function session_start
1 called from line 368 of file session.php in function require_once
2 called from line 75 of file config.php in function require
3 called from line 29 of file index.php

ERROR 2: session_regenerate_id() [function.session-regenerate-id]: Cannot regenerate session id - headers already sent
0 Error occurred on in function session_regenerate_id
1 called from line 372 of file session.php in function require_once
2 called from line 75 of file config.php in function require
3 called from line 29 of file index.php

ERROR 2: Cannot modify header information - headers already sent by (output started at /home/allau/public_html/mccorkell.info/cms/phpgedview/includes/functions/functions.php:500)