http://it.php.net/manual/en/info.con...execution-time

You can not change this setting with ini_set() when running in safe mode. The only workaround is to turn off safe mode or by changing the time limit in the php.ini.
mentre

http://it.php.net/manual/en/ini.core...i.memory-limit

Dai un occhio anche a
http://it.php.net/manual/en/configuration.changes.php

e
http://it.php.net/manual/en/ini.php#ini.list