How to run a cron from a php script.

[Robert Brookner]

I have a php script that is executed by a user and sets "fileone = 1" in the database.
After that script is executed, I would like to add a cron.php as a include.

I want the following php script to execute once automatically after 7 days has past

<?php
include "Dbcon.php";
$result = mysql_query("UPDATE myfile SET fileone='0' WHERE fileone='1'") 
or die(mysql_error());  
mysql_close();
?>

What I an example of a php script of what I need, but this example does not work.
Can someone help either make this script work or show me one that will?

#!usr/local/lib/php 
flag_file="/home/amour/public_html/phplogin/.cleanup_flag"
script_file="/home/amour/public_html/phplogin/cron.php"
offset_days=7
<?php
if ( -z $flag_file ){

        time_last_run=`cat $flag_file`;
        time_today=`date +%s`;

        time_diff=(($time_today-$time_last_run));
        time_offset=(($offset_days*86400));

        if ( "$time_diff" -ge "$time_offset" ){
        
                php $script_file;
                rm $flag_file;
        }
}
?>