Problème avec cURL

Bonzooooour à tous et toutes,
J'ai suivis le tutoriel abonnement premium paypal sans cake PHP mais j'ai une erreur. Voici mon code :
(Configuration de cURL)

$mail = 'xxxxx@gmail.com';  //idem
$name = 'Compte spécial';
$price =    '25.00';
$notify =   'http://xxxxx/ipn.php'; //  Url du ipn
$success    =   'http://xxxxx/success.php'; //  Url de la page retour success
$cancel =   'http://xxxxx/cancel.php';  //  Url de la page cancel
$custom =   '';

    $user = 'xxxxxxxxx'; // Utilisateur API
    $pwd =  'xxxxxx'; // Mot de passe API
    $signature  =   'xxxxxx'; // Signature de l'API

$request = array(
            'METHOD' => 'BMCreateButton',
            'VERSION' => '116',
            'USER' => $user,
            'PWD' => $pwd,
            'SIGNATURE' => $signature,
            'BUTTONCODE' => 'HOSTED',
            'BUTTONTYPE' => 'BUYNOW',
            'BUTTONSUBTYPE' => 'SERVICES',          
                           'L_BUTTONVAR0' => 'business='.$mail,
            'L_BUTTONVAR1' => "item_name=$name",
            'L_BUTTONVAR2' => "amount=$price",
            'L_BUTTONVAR3' => "currency_code=EUR",
            'L_BUTTONVAR4' => "no_note=1",
            'L_BUTTONVAR5' => "notify_url=$notify",
            'L_BUTTONVAR6' => "return=$success",
            'L_BUTTONVAR7' => "cancel=$cancel",
            'L_BUTTONVAR8' => "custom=$custom"
            );

        $request = http_build_query($request);
        $curlOptions = array(
            CURLOPT_URL => "https://api-3t.sandbox.paypal.com/nvp",
            CURLOPT_VERBOSE => 1,
            CURLOPT_SSL_VERIFYPEER => false,
            CURLOPT_SSL_VERIFYHOST => false,
            CURLOPT_RETURNTRANSFER => 1,
            CURLOPT_POSTFIELDS => $request
        );

        $ch = curl_init();
        curl_setopt_array($ch,$curlOptions);
        $response = curl_exec($ch);

        if(curl_errno($ch)){
            var_dump(curl_error($ch)); 
            die();
        }else{
            var_dump(curl_getinfo($ch, CURLINFO_HTTP_CODE));
            curl_close($ch);
            parse_str($response,$responseArray);
            var_dump($responseArray);
        }

J'ai cette erreur :

int(200) array(9) { "TIMESTAMP"]=> string(20) "2014-08-24T19:05:45Z" "CORRELATIONID"]=> string(13) "3a397994a1f73" "ACK"]=> string(7) "Failure" "VERSION"]=> string(3) "116" "BUILD"]=> string(8) "12471160" "L_ERRORCODE0"]=> string(5) "10002" "L_SHORTMESSAGE0"]=> string(14) "Security error" "L_LONGMESSAGE0"]=> string(28) "Security header is not valid" "L_SEVERITYCODE0"]=> string(5) "Error" }