Can't get this content spinning API to work with PHP

Can you help me get this content spinning API working? It was wrote to work with C# but is there a way I can get it to work using PHP? I've been trying to post to the URL stated on that page using cURL, but all I'm getting back is a blank page. Here's the code I'm using:

$url = "http://api.spinnerchief.com/apikey=YourAPIKey&username=YourUsername&password=YourPassword";

// Some content to POST
$post_fields = "SpinnerChief is totally free. Not a 'lite' or 'trial' version, but a 100% full version and totally free. SpinnerChief may be free, but it is also one of the most powerful content creation software tools available. It's huge user-defined thesaurus means that its sysnonyms are words that YOU would normally use in real life, not some stuffy dictionary definition. And there's more...SpinnerChief can only get better, because we listen to our users, We take onboard your ideas and suggestions, and we update SpinnerChief so that it becomes the software YOU want!";

$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_PORT, 9001);
curl_setopt($ch, CURLOPT_POST, 1);
curl开发者_Go百科_setopt($ch, CURLOPT_POSTFIELDS, $post_fields);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
$result = curl_exec($ch);
curl_close($ch);

echo $result;

Can anyone see something wrong I'm doing? Thanks a lot for the help.

---

The value for CURLOPT_POST should be 1, and the posted data should be set with CURLOPT_POSTFIELDS.