PHP表单验证代码过去工作得很好，现在已经停止工作了，我不想了；我不知道为什么

我的网站上有一些非常基本的php验证代码，它已经运行了很长一段时间。无论如何，我都不是php专家（我相信下面很明显）：），但到目前为止，这段代码一直可以满足我的需求。。。我最近意识到这个代码已经停止工作了，我不知道为什么。如有任何帮助，我们将不胜感激。我想服务器上可能有什么变化，所以我和我的主机公司聊了聊，他们向我保证没有任何变化，一定是代码错误。

以下是代码的基本部分：

<?php // Handle the form submission
    // VALIDATE Forms Required Fileds       
    //Check for name.       
    if (strlen($_POST['name']) > 0 ){
        $name = $name;
    } else {
        $name = NULL;
    }   
    //Check email was entered
    if (strlen($_POST['email'])=='') {
        $email = NULL;
    } elseif(!eregi("^[_a-z0-9-]+('.[_a-z0-9-]+)*@[a-z0-9-]+('.[a-z0-9-]+)*('.[a-z]{2,3})$", $_POST['email'])) {
        $email = "invalid";
    } else {
        $email = $email;
    }
    // END VALIDATION
    // If all is ok then handle form
    if ((isset($_POST['Submit']) || isset($_POST['Submit_x'])) && ($name && $email && $email != "invalid"))
    {       
        // Capture information and format for email
        $subject="Side Nav Form"; // Subject of Email
        $body = "Contact Us:'n'n";      
        $body .="Name..............: " ."$name'n";
        $body .="Email.............: " ."$email'n";
        $body .="Phone.............: " ."$phone'n'n";
        $body .="Reason for inquiry: " ."$inquiryReason1, $inquiryReason2, $inquiryReason3'n";
        $body .="Current Website...: " ."$current_site'n'n";
        $body .="Comments/Questions: " ."$addtlComments'n";
        //Email form results
        mail("xxx@xxx.com", $subject, $body, "From:" .$email);
        // Display thank you Message if form submitted successfully.
        echo '<h3>Thank you!</h3><p>We received your information and will get back to you as soon as possible.</p>';
    } else {    
        // If Validating form: Show validation errors.
        if ((isset($_POST['Submit']) || isset($_POST['Submit_x'])) && (!$name || !$email || $email == "invalid")) { 
        echo '<p class="error">';
             if (!$name) {
                    echo "*Please enter your name.<br />";
                    }
             if (!$email) {
                    echo "*Please enter your email address.<br />";
                    } 
             if ($email == "invalid") {
                    echo "*Please enter a valid email address. (xxx@xxx.xxx)";
                    } 
        echo '</p>';
        }
    // Display the form if user has not submitted successfully or at all.
?>
<fieldset><label for="name">*Name:</label> <input type="text" name="name" id="name" value="<?php if (isset($_POST['name'])) echo $_POST['name']; ?>" /></fieldset>
<fieldset><label for="email">*Email:</label> <input type="text" name="email" id="email" value="<?php if (isset($_POST['email'])) echo $_POST['email']; ?>" /></fieldset>
... rest of form fields...
<input name="Submit" type="submit" value="Submit" class="submit" />
</form>
<?php       
    } // End of Form Handler
?>