[jQuery] (validate) Problem with validate plugin at IE7

[jQuery] (validate) Problem with validate plugin at IE7

First, i'm very new at the jquery world so sorry if i'm posting
somehting very nooby.
i've downloaded and modified the validation plugin for jquery (found
at http://bassistance.de/jquery-plugins/jquery-plugin-validation/ )
it workd fine with chrome, firefox and IE8 but doesn't send the form
or appears messages when you view it with IE7
here's my code:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://
www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html;
charset=iso-8859-1" />
<title>Economia e Energia</title>
<link rel="stylesheet" type="text/css" href="style.css"/>
<link rel="stylesheet" type="text/css" href="form.css" />
<script src="jquery-1.3.2.js" type="text/javascript"></script>
<script src="jquery.validate.js" type="text/javascript"></script>
<script src="cmxforms.js" type="text/javascript"></script>
<script type="text/javascript">
$.validator.setDefaults({
    submitHandler: function() { alert("submitted!"); }
});
$().ready(function() {
    // validate signup form on keyup and submit
    $("#formcadastro").validate({
        rules: {
            nome: "required",
            sobrenome: "required",
            login: {
                required: true,
                minlength: 5
            },
            senha: {
                required: true,
                minlength: 5
            },
            csenha: {
                required: true,
                minlength: 5,
                equalTo: "#senha"
            },
            email: {
                required: true,
                email: true
            },
            cpf: {
                required: true,
                minlength:10
            },
            rg: "required",
            cidade: {
                required:true,
                minlength:4
            },
        },
        messages: {
            nome: "<p style='color:#F00'>Por favor digite o seu nome",
            sobrenome: "<p style='color:#F00'>Por favor digite o seu sobrenome</
p>",
            login: {
                required: "<p style='color:#F00'>Por favor digite seu login",
                minlength: "<p style='color:#F00'>Seu login deve ter no minimo
cinco caracteres"
            },
            senha: {
                required: "<p style='color:#F00'>Por favor digite uma senha",
                minlength: "<p style='color:#F00'>Sua senha deve ter no minimo
cinco caracteres"
            },
            csenha: {
                required: "<p style='color:#F00'>Por favor re-digite sua senha</
p>",
                minlength: "<p style='color:#F00'>Sua senha deve ter no minimo
cinco caracteres",
                equalTo: "<p style='color:#F00'>Por favor verifique se esta
inserida a mesma senha que no campo acima."
            },
            email: "<p style='color:#F00'>Por favor insira um e-mail valido</
p>",
            cpf: {
                required: "<p style='color:#F00'>Por favor insira seu CPF",
                minlength: "<p style='color:#F00'>CPF inv&aacute;lido"
            },
            rg: "<p style='color:#F00'>Por Favor insira seu RG",
            cidade: {
                required: "<p style='color:#F00'> Por favor insira sua cidade</
p>",
                minlength: "<p style='color:#F00'>Por favor insira o nome de sua
cidade com mais de quatro caracteres"
            },
        }
    });
    //code to hide topic selection, disable for demo
    var newsletter = $("#newsletter");
    // newsletter topics are optional, hide at first
    var inital = newsletter.is(":checked");
    var topics = $("#newsletter_topics")[inital ? "removeClass" :
"addClass"]("gray");
    var topicInputs = topics.find("input").attr("disabled", !inital);
    // show when newsletter is checked
    newsletter.click(function() {
        topics[this.checked ? "removeClass" : "addClass"]("gray");
        topicInputs.attr("disabled", !this.checked);
    });
});
</script>
</head>
<body>
<div id="tudo" align="center">
<?php include "topo.php" ?>
<div id="conteudo"><div id="enchespaco"></div>
<div id="cadastropg">
<form id='formcadastro' method='post' action='incluir.php'