trouble with cURL & Linkpoint

I'm having trouble getting cURL to work with a remote server. I'm using Linkpoint to process a credit card transaction. (Does anyone have any experience with Linkpoint?) I have tested my script on another server and cURL seems to retrieve the information fine. However, I'm getting a blank html page when I try the linkpoint form processor. When I submitted the form directly to Linkpoint, everything worked OK. Here's the script I submit to on my server: $postfields = array(); $postfields[] = array("bname", $_POST['bname']); $postfields[] = array("baddr1", $_POST['baddr1']); $postfields[] = array("baddr2", $_POST['baddr2']); $postfields[] = array("bcity", $_POST['bcity']); $postfields[] = array("bstate", $_POST['bstate']); $postfields[] = array("bzip", $_POST['bzip']); foreach($postfields as $subarray) {

     list($foo, $bar) = $subarray;
     $bar = urlencode($bar);
     $postedfields[]  = "$foo=$bar";

} $urlstring = join("\n", $postedfields); $urlstring = ereg_replace("\n", "&", $urlstring); $ch = curl_init("https://www.linkpointcentral.com/lpc/servlet/lppay");

        curl_setopt($ch, CURLOPT_HEADER, 0);
        curl_setopt($ch, CURLOPT_POST, 1);
        curl_setopt($ch, CURLOPT_POSTFIELDS, $urlstring);
        curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 0);
        curl_setopt($ch, CURLOPT_REFERER, "http://www.mysite.com/mypage.html");
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
        $data = curl_exec($ch);
        curl_close($ch);

echo $data;