Pourquoi ne Stripe.com de retour d'erreur (402) le Paiement Requis?

Je ne vois pas ce message d'erreur décrit dans les bandes API n'importe où. Quelqu'un sait ce qui se passe?

Voici mon VB.net code pour créer un client:

Function CreateStripeCustomer(ByVal Token As String) As String
    ''  The Stripe Account API Token - change this for testing 
    Dim STR_Stripe_API_Token As String = "sk_test_SECRET_TEST_KEY" '<-- test secret key. Change to live later.
    ''The Stripe API URL
    Dim STR_Stripe_API_URL As String = "https://api.stripe.com/v1/customers"
    ''Creates a Web Client
    Dim OBJ_Webclient As New System.Net.WebClient()
    ''Creates Credentials
    Dim OBJ_Credentials As New System.Net.NetworkCredential(STR_Stripe_API_Token, "MY_STRIPE.COM_PASSWORD")
    ''Sets the Credentials on the Web Client
    OBJ_Webclient.Credentials = OBJ_Credentials
    ''Creates a Transaction with Data that Will be Sent to Stripe
    Dim OBJ_Transaction As New System.Collections.Specialized.NameValueCollection()
    OBJ_Transaction.Add("email", "PERFECTLY_VALID_EMAIL")
    OBJ_Transaction.Add("card", "PERFECTLY VALID TOKEN RETURNED BY STRIPE.JS")
    ''The Stripe Response String
    Dim STR_Response As String = Encoding.ASCII.GetString(OBJ_Webclient.UploadValues(STR_Stripe_API_URL, OBJ_Transaction))
    Return STR_Response
End Function

La 402 de paiement "nécessaire" d'erreur qui se passe sur la ligne:

Dim STR_Response As String = Encoding.ASCII.GetString(OBJ_Webclient.UploadValues(STR_Stripe_API_URL, OBJ_Transaction))