[ASP.NET] UpdatePanel+ Validator +redirect = BOUM

<%@ Page Language="C#" MasterPageFile="~/MasterPage.master" AutoEventWireup="true" CodeFile="ajoutMembre.aspx.cs" Inherits="_Default" Title="Untitled Page" %>
<%@ Register Assembly="AjaxControlToolkit" Namespace="AjaxControlToolkit" TagPrefix="cc1" %>
<asp:Content ID="Content1" ContentPlaceHolderID="ContentPlaceHolder1" Runat="Server">
    <fieldset>
        <legend>Inscription d'un joueur (Etape 1/2)</legend>
        <div class="flottantDroite">
            <asp:UpdateProgress ID="UpdateProgress1" runat="server" >
                <ProgressTemplate>
                    <img src="img/barre.gif" alt="Connexion..."/><br />
                    Connexion serveur... patientez svp.
                </ProgressTemplate>
            </asp:UpdateProgress>
        </div>
        <asp:UpdatePanel ID="UpdatePanel1" runat="server">
            <ContentTemplate>
                <div class="centrer">
                    <asp:Label id="Label1" runat="server" CssClass="label" Text="Pseudo* :"></asp:Label> 
                    <asp:TextBox id="pseudo" runat="server" CssClass="input" AutoPostBack="true" OnTextChanged="checkPseudo"></asp:TextBox> 
                    <asp:Image id="ko" runat="server" CssClass="erreurImg" Visible="False" ImageUrl="~/img/ko.png"></asp:Image> 
                    <asp:Image id="ok" runat="server" CssClass="erreurImg" Visible="False" ImageUrl="~/img/ok.png"></asp:Image> 
                    <asp:Label id="ErreurPseudo" runat="server" CssClass="erreurMsg" Width="140px"></asp:Label> <br /><br />
                    <asp:Label id="Label2" runat="server" CssClass="label" Text="Password* :"></asp:Label> 
                    <asp:TextBox id="password" runat="server" CssClass="input" TextMode="Password"></asp:TextBox> 
                    <asp:RequiredFieldValidator id="RequiredFieldValidator1" runat="server" CssClass="erreurCombo" Width="167px" EnableClientScript="false" 
                        ForeColor="Transparent" SetFocusOnError="True" ErrorMessage="Password requis!" ControlToValidate="password"></asp:RequiredFieldValidator> 
                    <asp:RegularExpressionValidator id="RegularExpressionValidator2" runat="server" CssClass="erreurCombo" Width="165px" EnableClientScript="false" 
                        ForeColor="Transparent" SetFocusOnError="True" ErrorMessage="4 à 32 caractères!" ControlToValidate="password" ValidationExpression="^.{4,32}$"></asp:RegularExpressionValidator><br /><br />
                    <asp:Label id="Label3" runat="server" CssClass="label" Text="Email* :"></asp:Label> 
                    <asp:TextBox id="email" runat="server" CssClass="input"></asp:TextBox> 
                    <asp:RegularExpressionValidator id="RegularExpressionValidator1" runat="server" CssClass="erreurCombo" Width="164px" EnableClientScript="false" 
                        ForeColor="Transparent" SetFocusOnError="True" ErrorMessage="Forme: x@x.x" ControlToValidate="email" ValidationExpression="\w+([-+.']\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*"></asp:RegularExpressionValidator> 
                    <asp:RequiredFieldValidator id="RequiredFieldValidator2" runat="server" CssClass="erreurCombo" Width="163px" EnableClientScript="false" 
                        ForeColor="Transparent" SetFocusOnError="True" ErrorMessage="Email requis!" ControlToValidate="email"></asp:RequiredFieldValidator><br /><br />
                    <asp:Button id="inscription" runat="server" Text="Inscription" Enabled="false" OnClick="inscription_Click"></asp:Button> 
                </div>
            </ContentTemplate>
        </asp:UpdatePanel>
    </fieldset>
</asp:Content>

protected void inscription_Click(object sender, EventArgs e)
    {
        Joueurs joueur = new Joueurs();
        joueur.setAcces(0);
        joueur.setEmail(email.Text);
        string passwordMD5 = System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(password.Text, "md5");
        joueur.setPassword(passwordMD5);
        joueur.setPseudo(pseudo.Text);
        DateTime today = DateTime.Now;
        string jourM = ""+today.Day;
        if (jourM.Length < 2)
            jourM = "0" + today.Day;
        joueur.setDateInscription(today.Year+"-"+today.Month+"-"+jourM);
        Joueurs.ajouter(joueur);
        Session["joueur"] = joueur;
        //Response.Redirect("ajoutMembre2.aspx");
    }