Using CURL To Run PHP Scripts - php

Question

I have created an internal billing system where i need to generate invoices for a customer based on their billing schedule however i have run into a problem when running PHP scripts from CURL and was wondering if there is any way round it
I currently have a CRON task that runs a php script called crontask.php
crontask.php then calculates if the customer needs an invoice generated and sent to them via email. If it calculates that it does then it will try and call an url that will create the Invoice and send the email using CURL i.e (www.internal.co.uk/invoicing/geninvoice.php?CUST=10)
function get_web_page($url)
{
$ua = 'Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US) AppleWebKit/525.13 (KHTML, like Gecko) Chrome/0.A.B.C Safari/525.13';
echo "curl:url<pre>".$url."</pre><BR>";
$options = array(
CURLOPT_RETURNTRANSFER => true, // return web page
CURLOPT_HEADER => true, // don't return headers
CURLOPT_FOLLOWLOCATION => true, // follow redirects
CURLOPT_ENCODING => "", // handle all encodings
CURLOPT_USERAGENT => $ua, // who am i
CURLOPT_AUTOREFERER => true, // set referer on redirect
CURLOPT_CONNECTTIMEOUT => 15, // timeout on connect
CURLOPT_TIMEOUT => 15, // timeout on response
CURLOPT_MAXREDIRS => 10, // stop after 10 redirects
);
$ch = curl_init($url);
curl_setopt_array( $ch, $options );
$content = curl_exec( $ch );
$err = curl_errno( $ch );
$errmsg = curl_error( $ch );
$header = curl_getinfo( $ch,CURLINFO_EFFECTIVE_URL );
curl_close( $ch );
if(isset($header['errno'])) {
$header['errno'] = $err;
$header['errmsg'] = $errmsg;
}
//change errmsg here to errno
if (isset($errno)) {
echo "CURL:".$errmsg."<BR>";
}
return $content;
}
When running this i am getting access denied when trying to run from curl in PHP,
The server is running on virtualmin/webmin and i have root access, is there something i need to change or add authentication to the script?