php_value safe_mode off
inside the .htaccess file to turn it OFF.
Some hosting panels also have a place in the options section for turning safe mode off. It all depends on the hosting company. Some will take the time to secure their servers properly, and others use the shotgun approach and restrict anything that might cause a problem. The cheaper the hosting, the more restrictive they tend to be.
¿Where can I find the - htaccess file?