[jQuery] problem with validation plugin using the remote option

[rmirabelle]

I'm having a problem with the validation plugin.  Any time I try to
use the remote option, I get the same javascript error, regardless of
my configuration settings.  The error is this:

Error: this.settings.messages[element.name] is undefined
Source File: http://localhost/toldya6/liquid/scripts/js/jquery/validate.js
Line: 16

Here's the code:

$().ready(function() {
        $('#frm_user').validate({
                errorContainer: "#invalid",
                rules: {
                password: "required",
                confirm_password: { equalTo: "#password" },
                        email: {
                                remote: 'check-email.php'
                        }
                }
        });
});

my check-email.php file does only this:

<?php echo 'true' ?>

my form looks like this:

 <form id="frm_user" name="frm_user" method="post" action="<?php echo
$_SERVER['PHP_SELF'] ?>" class="liquidform">
        <fieldset class="overlay">
          <table width="100%" border="0" cellspacing="0"
cellpadding="0">
            <tr>
              <td><ol>
                  <li class="last">
                    <label for="email">Your Email <em>*</em></label>
                    <input type="text" id="email" name="email"
value="<?php echo $user->email ?>" maxlength="80"
class="{required:true, email:true}">
                  </li>
                  <li class="last">
                    <label for="btn_submit"></label>
                    <input type="image" id="btn_submit"
name="btn_submit" src="../images/buttons/next_step_on.gif" />
                  </li>
                </ol></td>
            </tr>
          </table>
        </fieldset>
      </form>

the error also appears if I remove the inline class="{required:true,
email:true}" from the email field.

Help!