sfDoctrineGuardPlugin : signin form, error 'csrf token : required'

Question

Hello,

I have just installed sfGuardPlugin to manage my user. But since I have try to customize the signin page, I have an error "csrf token : required". And I don't find where the error come from, I think I didn't change other thing that the template.

My signin form :

<?php use_helper('I18N') ?>

<span id='message'>Vous devez vous connecter pour pouvoir accéder à ce logiciel</span>

<form action="<?php echo url_for('@sf_guard_signin') ?>" method="post">

    <?php $routes = $sf_context->getRouting()->getRoutes() ?>
    <?php if (isset($routes['sf_guard_forgot_password'])): ?>
       <a href="<?php echo url_for('@sf_guard_forgot_password') ?>"><?php echo __('Forgot your password?', null, 'sf_guard') ?></a>
    <?php endif; ?>

    <?php if (isset($routes['sf_guard_register'])): ?>
       &nbsp; <a href="<?php echo url_for('@sf_guard_register') ?>"><?php echo __('Want to register?', null, 'sf_guard') ?></a>
    <?php endif; ?>

    <?php echo $form->renderHiddenFields() ?>
    <?php echo $form->renderGlobalErrors() ?>

    <fieldset>
        <table>
            <tr>
                <th colspan="3" class='error'><?php echo $form['username']->renderError() ?></th>
            </tr>
            <tr>
                <th><?php echo $form['username']->renderLabel() ?> :</th>
                <td><?php echo $form['username'] ?></td>
            </tr>

            <tr>
                <th colspan="3" class='error'><?php echo $form['password']->renderError() ?></th>
            </tr>
            <tr>
                <th><?php echo $form['password']->renderLabel() ?> :</th>
                <td><?php echo $form['password'] ?></td>
            </tr>

            <tr>
                <th colspan="3" class='error'><?php echo $form['remember']->renderError() ?></th>
            </tr>
            <tr>
                <th><?php echo $form['remember']->renderLabel() ?> :</th>
                <td id='automatique'><?php echo $form['remember'] ?></td>
            </tr>
        </table>
    </fieldset>

    <div id='boutons'>
        <input type="submit" value="<?php echo __('Se connecter', null, 'sf_guard') ?>" />
        <input type="reset" value="Réinitialiser"/>
    </div>
</form>