Getting External API to work: Empty result

[shout]

I am wrestling with the documentation trying to figure out what I need to do to make the external API work. I've created a php file and placed it in the WHMCS directory, and I think I have it set up correctly according to the documentation, but it always gives an empty response.

 

I am trying to do a module password change as described here.

 

Here is the code:

 

<?php
$url = "path/to/includes/api.php"; 
$username = "admin"; 
$password = "mysupersecurepassword"; 

$postfields["username"] = $username;
$postfields["password"] = md5($password);
$postfields["action"] = "modulechangepw";
$postfields["serviceid"] = "11";
$postfields["servicepassword"] = "anewpassword";

$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_TIMEOUT, 100);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS, $postfields);
$data = curl_exec($ch);
curl_close($ch);

$data = explode(";",$data);
foreach ($data AS $temp) {
  $temp = explode("=",$temp);
  $results[$temp[0]] = $temp[1];
}

if ($results["result"]=="success") {
   echo "OK!";
} else {
   echo $results["result"] . "The following error occured: ". $results["message"];
}

?>

 

The output page is simply:

 

The following error occurred: